TITLE 6. WATER WELL STANDARDS ORDINANCE

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Environmental Code

TITLE 6. WATER WELL STANDARDS ORDINANCE

(Adopted by the Tribe 04/27/19)

CHAPTER I. INTRODUCTION

Improperly constructed, altered, maintained, or destroyed wells are a potential pathway for

introducing poor quality water, pollutants, and contaminants to good-quality groundwater. The

potential for groundwater quality degradation increases as the number of wells and borings in the

area increases.

Improperly constructed, altered, maintained, or destroyed wells can facilitate groundwater quality

degradation by allowing:

e Pollutants, contaminants, and water to enter a well bore or casing;

e Poor quality surface and subsurface water, pollutants, and contaminants to move between

the casing and borehole wall;

¢ Poor quality groundwater, pollutants, and contaminants to move from one stratum or

aquifer to another; and,

e The well bore to be used for illegal waste disposal.

Permanently inactive or “abandoned” wells that have not been properly destroyed pose a serious

threat to water quality. They are frequently forgotten and become dilapidated with time, and thus

can become conduits for groundwater quality degradation. In addition, humans and animals can

fail into wells left open at the surface.

SECTION 1. Limitation of Standards

In some cases, it may be necessary for the Dry Creek Rancheria Department of Environmental

Protection (DEP) to substitute alternate measures or standards to provide protection equal to that

otherwise afforded by DEP standards. Such cases arise from practicalities in applying standards,

and from variations in geologic and hydrologic conditions. Because it is impractical to prepare

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“site-specific” standards covering every conceivable case, provision has been made for deviation

from the standards.

Standards in this ordinance do not ensure proper construction or function of any type of well.

Proper well design and construction practices require the use of these standards together with

accepted industry practices, regulatory requirements, and consideration of site conditions.

It is the ultimate responsibility of the well owner and/or the owner's technical and/or contractor

representative(s) to ensure that a well does not constitute a significant pathway for the movement

of poor-quality water, pollutants, or contaminants; does not constitute a public nuisance or

hazard; and, adequately performs a desired function. The Department accepts no responsibility

for improper design, construction, alteration, maintenance, function, or destruction of individual

wells, and the Tribe has not waived its sovereign immunity to any claim related to the same.

SECTION 2. Applicability

Construction standards presented in this ordinance apply to all water wells, monitoring wells, and

cathodic protection wells constructed after the date of this ordinance. Alteration, maintenance, and

destruction standards presented in this supplement apply to all water wells, monitoring wells,

cathodic protection wells, and “borings” regardless of their original date of construction.

CHAPTER 2. STANDARDS

The standards presented in this chapter are intended to apply to the construction (including major

reconstruction) or decommissioning of water wells throughout the lands of Dry Creek Rancheria.

However, under certain circumstances, adequate protection of groundwater quality may require

more stringent standards than those presented here; under other circumstances, it may be necessary

to substitute other measures which will provide protection equal to that provided by these

standards. Such situations arise from practicalities in applying any standards or, in this case, from

anomalies in groundwater geology or hydrology. Since it is impractical to prepare standards for

every conceivable situation, provision has been made for deviation from the standards as well as

for additional ones

SECTION 1. Definitions

(A) Well or Water Wells. Any artificial excavation constructed by any method for the purpose of

extracting water from, or injecting water into, the underground. This definition shall not include:

(1) oil and gas wells, or geothermal wells. except those wells converted to use as water wells; or

(2) wells used for the purpose of (a) dewatering excavations during construction, or (b) stabilizing

hillsides or earth embankments.

(B) Community Water Supply Well. A water well used to supply water for domestic purposes in

systems subject to the Federal Safe Drinking Water Act. Included are wells supplying public water

systems classified by the U.S. Environmental Protection Agency as "Noncommunity water

systems" and "State small water systems" (California Waterworks Standards, Title 22, California

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Administrative Code). Such wells are variously referred to as "Municipal Wells", "City Wells", or

"Public Water Supply Wells".

individual residence or systems of four or less residential service connections (or "hook-ups" as

they are often called).

(D) Industrial Wells. Water wells used to supply industry on an individual basis (in contrast to

supplies provided through community systems).

(E) Agricultural Wells. Water wells used to supply water only for irrigation or other agricultural

purposes, including so-called "stock wells".

(F) Recharge or Injection Wells. Wells constructed to introduce water into the ground as a means

of replenishing groundwater basins, repelling the intrusion of seawater or disposing of waste water.

(G) Horizontal Wells. Water wells drilled horizontally or at an angle with the horizon (as

contrasted with the common vertical well). This definition does not apply to horizontal drains or

"wells" constructed to remove subsurface water from hillsides, cuts, or fills (such installations are

used to prevent or correct conditions that produce landslides).

(H) Exploration Hole (or Boring). An uncased, temporary excavation whose purpose is the

determination of hydrologic conditions at a site.

(1) Test Wells. Wells constructed to obtain information needed for design of other wells. Test wells

should not be confused with "exploration holes", which are temporary. Test wells are cased and

can be converted to other uses such as groundwater monitoring and, under certain circumstances,

to production wells.

(J) Inactive or Standby Well. A well not routinely operating, but capable of being made operable

with a minimum effort.

(K) Enforcing Agency. An agency designated by duly authorized Tribal or Federal government to

administer and enforce laws or ordinances pertaining to the construction, alteration, maintenance,

and destruction of water wells. The USEPA or the DEP is the enforcing agency for community

water supply wells.

(L) Registered Geologist. Any person or agency in possession of a valid California registration as

a geologist.

SECTION 2. Application to Types of Wells

Except as prescribed in Sections 3 and 4 of this Chapter, these standards shall apply to all types of

wells described in Section 1. Before a change of use is made of a well, compliance shall be made

with the requirements for the new use as specified herein.

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SECTION 3. Exemption Due to Unusual Conditions

If the enforcing agency finds that compliance with any of the requirements prescribed herein is

impractical for a particular location because of unusual conditions, or if compliance would result

in construction of an unsatisfactory well, the enforcing agency may waive compliance and

prescribe alternative requirements which are equal to these standards in terms of protection

obtained.

SECTION 4. Exclusions

The standards prescribed in Part II, "Construction", do not apply to exploration and test holes.

However, the provisions of Section 7 "Reports" and Part II, "Well Destruction", do apply to these

holes. Springs are excluded from these standards.

SECTION 5. Special Standards

(A) In locations where existing geologic or groundwater conditions require standards more

restrictive than those described herein, such special additional standards may be prescribed by the

enforcing agency.

(B) Special standards are necessary for the construction of recharge or injection wells, horizontal

wells and other unusual types of wells. Design of these wells shall be conducted by a Registered

Geologist and is subject to the approval of the enforcing agency.

SECTION 6. Well Drillers

The construction, alteration, or destruction of wells shail be performed by contractors licensed in

accordance with the provisions of the Contractor’s License Law (Chapter 9, Division 3, of the

Business and Professions Code unless exempted by that act.

SECTION 7. Reports

Reports concerning the construction, alteration, or destruction of water wells shall be filed with

the DEP within 30 days of such activity.

SECTION 8. Well Location with Respect to Pollutants and Contaminants, and Structures

(A) Separation. All water wells shall be located an adequate horizontal distance from known or

potential sources of pollution and contamination. Such sources include, but are not limited to:

(1) sanitary, industrial, and storm sewers;

(2) septic tanks and leachfields;

(3) sewage and industrial waste ponds;

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(4) barnyard and stable areas;

(5) feedlots;

(6) solid waste disposal sites;

(7) above and below ground tanks and pipelines for storage and conveyance of petroleum

products or other chemicals; and,

(8) storage and preparation areas for pesticides, fertilizers, and other chemicals.

Consideration should also be given to adequate separation from sites or areas with known or

suspected soil or water pollution or contamination.

The following horizontal separation distances are generally considered adequate where a

significant layer of unsaturated, unconsolidated sediment less permeable than sand is encountered

between ground surface and groundwater. These distances are based on present knowledge and

past experience. Local conditions may require greater separation distances to ensure groundwater

quality protection.

: j | Minimum Horizontal |

sietiiien teint | Separation Distance Between |

a. Well and Known or

Contamination Source | ‘

Potential Source |

Any sewer (sanitary, industrial, or storm; main or | 50 feet

lateral) |

Watertight septic tank or subsurface sewage leaching | 100 feet

field | |

| Cesspool or seepage pit | 150 feet |

"Animal or fowl enclosure | 100 feet |

If the well is a radial collector well, minimum separation distances shall apply to the furthest

extended point of the well.

Many variables are involved in determining the safe separation distance between a well and a

potential source of pollution or contamination. No set separation distance is adequate and

reasonable for all conditions. Determination of the safe separation distance for individual wells

requires detailed evaluation of existing and future site conditions.

Where, in the opinion of the DEP, adverse conditions exist, the above separation distances shall

be increased, or special means of protection, particularly in the construction of the well, shall be

provided, such as increasing the length of the annular seal.

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Lesser distances than those listed above may be acceptable where physical conditions preclude

compliance with the specified minimum separation distances and where special means of

protection are provided. Lesser separation distances must be approved by the DEP, at its discretion,

on a case-by-case basis.

(B) Gradients. Where possible a well shall be located up the groundwater gradient from potential

sources of pollution or contamination. Locating wells up gradient from pollutant and contaminant

sources can provide an extra measure of protection for a well. However, consideration should be

given that the gradient near a well can be reversed by pumping, as shown in Figure 3, or by other

influences.

of the well casing shall terminate above grade and above known levels of flooding caused by

drainage or runoff from surrounding land. This is defined as any area within the flood plain of a

100-year flood.

If compliance with the casing height requirement for community water supply wells and other

water wells is not practical, the DEP shall require alternate means of protection.

Surface drainage from areas near the well shall be directed away from the well. If necessary, the

area around the well shall be built up so that drainage moves away from the well.

(D) Accessibility. All wells shall be located an adequate distance from buildings and other

structures to allow access for well modification, maintenance, repair, and destruction, unless

otherwise approved by the DEP.

SECTION 9. Sealing the Upper Annular Space

The space between the well casing and the wall of the drilled hole, often referred to as the annular

space, shall be effectively sealed to prevent it from being a preferential pathway for movement of

poor-quality water, pollutants, or contaminants. In some cases, secondary purposes of an annular

seal are to protect casing against corrosion or degradation, ensure the structural integrity of the

casing, and stabilize the borehole wall.

(A) Minimum Depth of Annular Surface Seal. The annular surface seal for various types of water

wells shall extend from ground surface to the following minimum depths:

Minimum Depth Seal Must

Well Type Extend Below Ground Surface |

Community Water Supply 80 feet |

' Industrial | 50 feet |

"Individual Domestic 50 feet |

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| Agricultural . 20 feet

- Air-Conditioning 20 feet

~All Other types 20 feet

(B)

(1) Shallow groundwater. Exceptions to minimum seal depths can be made for shallow

wells at the approval of the DEP, where the water to be produced is at a depth less than 20

feet. In no case shall an annular seal extend to a total depth less than 10 feet below land

surface. The annular seal shall be no less than 10 feet in length.

Caution shall be given to locating a well with a 'reduced' annular seal with respect to

sources of pollution or contamination. Such precautions include horizontal separation

distances greater than those listed in Section 8 of this Chapter.

(2) Encroachment on known or potential sources of pollution or contamination. When, at

the approval of the DEP, a water well is to be located closer to a source of pollution or

contamination than allowed by Section 8 of this Chapter, the annular space shall be sealed

from ground surface to the first impervious stratum, if possible. The annular seal for all

such wells shall extend to a minimum depth of 50 feet.

(3) Vaults. With the DEP’s approval, which may be given at its discretion, the top of an

annular surface seal and well casing can be below ground surface where traffic or other

conditions require, if the seal and casing extend to a watertight and structurally sound

subsurface vault, or equivalent feature. In no case shall the top of the annular surface seal

be more than 4 feet below ground surface. The vault shall extend from the top of the annular

seal to at least ground surface.

The use of subsurface vaults to house the top of water wells below ground surface is rare

and is discouraged due to susceptibility to the entrance of surface water, pollutants, and

contaminants. Where appropriate, pitless adapters should be used in place of vaults.

space:

(1) Wells drilled in unconsolidated, caving material. An ‘oversized’ hole, at least 4 inches

greater in diameter than the outside diameter of the well casing, shall be drilled and a

conductor casing temporarily installed to at least the minimum depth of annular seal

specified in Subsection A, above. Permanent conductor casing may be used if it is installed

in accordance with Item 3 and Item 5, below and if it extends at least to the depth specified

in Subsection A, above. One purpose of conductor casing is to hold the annular space open

during well drilling and during the placement of the well casing and annular seal.

Temporary conductor casing shall be withdrawn as sealing material is placed between the

well casing and borehole wall, as shown in Figure 4A. Sealing material shall be placed at

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least within the interval specified in Subsection A, above. The sealing material shall be

kept at a sufficient height above the bottom of the temporary conductor casing as it is

withdrawn to prevent caving of the borehole wall.

Temporary conductor casing may be left in place in the borehole after the placement of the

annular seal only if it is impossible to remove because of unforeseen conditions and not

because of inadequate drilling equipment, or if its removal will seriously jeopardize the

integrity of the well and the integrity of subsurface barriers to pollutant or contaminant

movement. Temporary conductor casing may be left in place only at the approval of the

enforcing agency on a case-by-case basis.

Every effort shall be made to place sealing material between the outside of temporary

conductor casing that cannot be removed and the borehole wall to fill any possible gaps or

voids between the conductor casing and the borehole wall. At least two inches of sealing

material shall be maintained between the conductor casing and well casing. At a minimum,

sealing material shall extend through intervals specified in Subsection A, above.

Sealing material can often be placed between temporary conductor casing that cannot be

removed and the borehole wall by means of pressure grouting techniques, as described

below. Other means of placing sealing material between the conductor casing and the

borehole wall can be used, at the approval of the enforcing agency.

Pressure grouting shall be accomplished by perforating temporary conductor casing that

cannot be removed, in place. The perforations are to provide passages for sealing material

to pass through the conductor casing to fill any spaces and voids between the casing and

borehole wail. Casing perforations shall be a suitable size and density to allow the passage

of sealing materials through the casing and the proper distribution of sealing material in

spaces between the casing and borehole wall. At a minimum, the perforations shall extend

through the intervals specified in Subsection A, above, unless otherwise approved by the

DEP.

Temporary conductor casing that must be left in place shall be perforated immediately

before sealing operations begin to prevent drilling or well construction operations from

clogging casing perforations. Once the casing has been adequately perforated, sealing

material shall be placed inside the conductor casing and subjected to sufficient pressure to

cause the sealing material to pass through the conductor casing perforations and completely

fill any spaces or voids between the casing and borehole wall, at least within the intervals

specified in Subsection A, above. Sealing material shall consist of neat cement, or bentonite

prepared from powdered bentonite and water, unless otherwise approved by the DEP.

Sealing material must also fill the annular space between the conductor casing and the well

casing within required sealing intervals.

(2) Wells drilled_in unconsolidated material with significant clay layers. An 'oversized'

hole, at least 4 inches greater in diameter than the outside diameter of the well casing, shall

be drilled to at least the depth specified in Subsection A, above, and the annular space

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between the borehole wall and the well casing filled with sealing material in accordance

with Subsection A, above . If a significant layer of clay or clay-rich deposits of low

permeability is encountered within 5 feet. of the minimum seal depth prescribed in

Subsection A, above, the annular seal shall be extended at least 5 feet into the clay layer.

Thus, the depth of seal could be required to be extended as much as another 10 feet. If the

clay layer is less than 5 feet in total thickness, the seal shall extend through its entire

thickness.

If caving material is present within the interval specified in Subsection A, a temporary

conductor casing shall be installed to hold the borehole open during well drilling and

placement of the casing and annular seal, in accordance with the requirements of Item 1,

above. Permanent conductor casing may be used if it is installed in accordance with Item

3 and Item 5, below, and it extends to at least the depth specified in Subsection A, above.

(3) Wells drilled in soft consolidated formations (extensive clays, sandstones, etc.). An

‘oversized’ hole, at least 4 inches greater than the outside diameter of the well casing, shall

be drilled to at least the depth specified in Subsection A, above. The space between the

well casing and the borehole shall be filled with sealing material to at least the depth

specified in Subsection A, above.

If a permanent conductor casing is to be installed to facilitate the construction of the well,

an oversized hole, at least 4 inches greater in diameter than the outside surface of the

permanent conductor casing, shall be drilled to the bottom of the conductor casing or to at

least the depth specified in Subsection A, above, and the annular space between the

conductor casing and the borehole wall filled with sealing material. In some cases, such as

in cable tool drilling, it may be necessary to extend permanent conductor casing beyond

the depth of the required depth of the annular surface seal in order to maintain the borehole.

Sealing material is not required between conductor casing and the borehole wall other than

the depths specified in Subsection A of this Section, and Section 13 of this Chapter.

(4) Wells situated in "hard" consolidated formations (crystalline or metamorphic rock). An

oversized hole shall be drilled to the depth specified in Subsection A of this Section, and

the annular space filled with sealing material. If there is significant overburden, a conductor

casing may be installed to retain it. If the material is heavily fractured, the seal should

extend into a solid material. If the well is to be open-bottomed (lower section uncased), the

casing shall be seated in the sealing material.

(5) Gravel packed wells.

(a)With conductor casing. An oversized hole, at least 4 inches greater than the

diameter of the conductor casing, shall be drilled to the depth specified in

Subsection A, above and the annular space between the conductor casing and

drilled hole filled with sealing material. (In this case the gravel pack may extend to

the top of the well but to prevent contamination by surface drainage, a welded cover

shall be installed over the top in the space between the conductor casing and the

production casing).

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(b) Without conductor casing. An oversized hole at least 4 inches greater in

diameter than the production casing, shall be drilled to the depth specified in

Subsection A, above and the annular space between the casing and drilled hole

filled with sealing material. If gravel fill pipes are installed through the seal, the

annular seal shall be of sufficient thickness to assure that there is a minimum of 2

inches between the gravel fill pipe and the wall of the drilled hole. The gravel pack

shall terminate at the base of the seal. If a temporary conductor casing is used, it

shall be removed as the sealing material is placed.

(6) For wells situated in circumstances differing from those described above, the sealing

conditions shall be as prescribed by the DEP.

(7) Converted_wells. Wells converted from one use to another, particularly those

constructed in prior years without annular seals, shall have annular seals installed to the

depth required in Subsection A, above and at the thickness described in Subsection E.

Where it is anticipated that a well will be converted to another use, the DEP may require

the installation of a seal to the depth specified for community water supply wells.

(8) Wells that penetrate zones containing poor-quality water, pollutants, or contaminants.

If geologic units or fill known or suspected to contain poor- quality water, pollutants, or

contaminants are penetrated during drilling, and, the possibility exists that poor-quality

water, pollutants, or contaminants could move through the borehole during drilling and

well construction operations and significantly degrade groundwater quality in other units

before sealing material can be installed, then precautions shall be taken to seal off or

‘isolate' zones containing poor-quality water, pollutants, and contaminants during drilling

and well construction operations. Special precautions could include the use of temporary

or permanent conductor casing, borehole liners, and specialized drilling equipment. The

use of conductor casing is described in Subsection 1 of this Section.

(D) Conductor Casing. For community water supply wells, the minimum thickness of steel

conductor casing shall be 1/4 inch for single casing or a minimum of No. 10 U. S. Standard Gage

for double casing. Steel used for steel casing shall conform to the specifications for steel casing

described in Section 12.

(E) Sealing Material. Sealing material shall consist of neat cement, sand cement, concrete, or

bentonite. Cuttings from drilling, or drilling mud, shall not be used for any part of the sealing

material.

(1) Water. Water used to prepare sealing mixtures should generally be of drinking water

quality, shall be compatible with the type of sealing material used, be free of petroleum

and petroleum products, and be free of suspended matter. In some cases, water considered

nonpotable, with a maximum of 2,000 milligrams per liter chloride and 1,500 mg/l sulfate,

can be used for cement-based sealing mixtures. The quality of water to be used for sealing

mixtures shall be determined where unknown.

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(2) Cement. Cement used in sealing mixtures shall meet the requirements of American

Society for Testing and Materials C150, Standard Specification for Portland Cement,

including the latest revisions thereof.

Types of Portland cement available under ASTM C150 for general construction are:

Type I - General purpose. Similar to American Petroleum Institute Class A.

Type II - Moderate resistance to sulfate. Lower heat of hydration than Type I. Similar to

API Class B.

Type Il - High early strength. Reduced curing time but higher heat of hydration than Type

I. Similar to API Class C.

Type IV - Extended setting time. Lower heat of hydration than Types I and II.

Type V - High sulfate resistance.

Special cement setting accelerators and retardants and other additives may be used in some

cases. Special field additives for Portland cement mixtures shall meet the requirements of

ASTM C494, Standard Specification for Chemical Admixtures for Concrete, and latest

revision thereof.

Hydrated lime may be added up to 10 percent of the volume of cement used to make the

seal mix more fluid. Bentonite may be added to cement-based mixes, up to 6 percent by

weight of cement used, to improve fluid characteristics of the sealing mix and reduce the

rate of heat generation during setting.

Dry additives should be mixed with dry cement before adding water to the mixture to

ensure proper mixing, uniformity of hydration, and an effective and homogeneous seal.

The water demand of additives shall be taken into account when water is added to the mix.

Minimum times required for sealing materials containing Portland cement to set and begin

curing before construction operations on a well can be resumed are:

(a) Types | and II cement — 24 hours

(b) Type III cement — 12 hours

Type IV cement is seldom used for annular seals because of its extended setting time.

Allowable setting times may be reduced or lengthened by use of accelerators or retardants

specifically designed to modify setting time, at the approval of the DEP.

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More time shall be required for cement-based seals to cure to allow greater strength when

construction or development operations following the placement of the seal may subject

casing and sealing materials to significant stress. Subjecting a well to significant stress

before a cement-based sealing material has adequately cured can damage the seal and

prevent proper bonding of cement-based sealants to casing(s).

If plastic well casing is used, care shall be exercised to control the heat of hydration

generated during the setting and curing of cement in an annular seal. Heat can cause plastic

casing to weaken and collapse. Heat generation is a special concern if thin-wall plastic well

casing is used, if the well casing will be subject to significant net external pressure before

the setting of the seal, and/or if the radial thickness of the annular seal is large. Additives

that accelerate cement setting also tend to increase the rate of heat generation during setting

and, thus, should be used with caution where plastic casing is employed.

The temperature of a setting cement seal can be lowered by circulating water inside the

well casing and/or by adding bentonite to the cement mixture, up to 6 percent by weight of

cement used.

Cement-based sealing material shall be constituted as follows:

(a) Neat Cement. For Types I or II Portland cement, neat cement shall be mixed at

a ratio of one 94-pound sack of Portland cement 5 to 6 gallons of 'clean' water.

Additional water may be required where special additives, such as bentonite, or

‘accelerators’ or 'retardants' are used.

(b) Sand Cement. Sand-cement shall be mixed at a ratio of not more than 188

pounds of sand to. one 94-pound sack of Portland cement (2 parts sand to 1-part

cement, by weight) and about 7 gallons of clean water, where Type I or Type II

Portland cement is used. This is equivalent to a'10.3 sack mix.’ Less water shall be

used if less sand than 2 parts sand per one-part cement by weight is used. Additional

water may be required when special additives, such as bentonite, or ‘accelerators’

or 'retardants' are used.

large-diameter wells. The proper use of aggregate can decrease the permeability of

the annular seal, reduce shrinkage, and reduce the heat of hydration generated by

the seal.

Concrete shall consist of Portland cement and aggregate mixed at a ratio of at least

six-94-pound sacks of Portland cement per cubic yard of aggregate. A popular

concrete mix consists of eight-94-pound sacks of Type I or Type II Portland cement

per cubic yard of uniform 3/8-inch aggregate.

In no case shall the size of the aggregate be more than 1/5 the radial thickness of

the annular seal. Water shall be added to concrete mixes to attain proper consistency

for placement, setting, and curing.

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(d) Mixing. Cement-based sealing materials shall be mixed thoroughly to provide

uniformity and ensure that no ‘lumps' exist.

Ratios of the components of cement-based sealing materials can be varied

depending on the type of cement and additives used. Variations must be approved

by the enforcing agency.

(3) Bentonite. Bentonite clay in 'gel' form has some of the advantages of cement-based

sealing material. A disadvantage is that the clay can sometimes separate from the claywater mixture.

Although many types of clay mixtures are available, none has sealing properties

comparable to bentonite clay. Bentonite expands significantly in volumes when hydrated.

Only bentonite clay is an acceptable clay for annular seals.

Unamended bentonite clay seals should not be used where structural strength of the seal is

required, or where it will dry. Bentonite seals may have a tendency to dry, shrink and crack

in arid and semi-arid areas of California where subsurface moisture levels can be low.

Bentonite clay seals can be adversely affected by subsurface chemical conditions, as can

cement-based materials.

Bentonite clay shall not be used as a sealing material if roots from trees and other deeprooted plants might invade and disrupt the seal, and/or damage the well casing. Roots may

grow in an interval containing a bentonite seal depending on surrounding soil conditions

and vegetation.

Bentonite-based sealing material shall not be used for sealing intervals of fractured rock or

sealing intervals of highly unstable, unconsolidated material that could collapse and

displace the sealing material, unless otherwise approved by the DEP. Bentonite clay shall

not be used as a sealing material where flowing water might erode it.

Bentonite clay products used for sealing material must be specifically prepared for such

use. Used drilling mud and/or cuttings from drilling shall not be used in sealing material.

Bentonite used for annular seals shall be commercially prepared, powdered, granulated,

pelletized, or chipped/crushed sodium montmorillonite clay. The largest dimension of

pellets or chips shall be less than 1/5 the radial thickness of the annular space into which

they are placed.

Bentonite clay mixtures shall be thoroughly mixed with clean water prior to placement. A

sufficient amount of water shall be added to bentonite to allow proper hydration.

Depending on the bentonite sealing mixture used, | gallon of water should be added to

about every 2 pounds of bentonite. Water added to bentonite for hydration shall be of

suitable quality and free of pollutants and contaminants.

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Bentonite preparations normally require % to 1 hour to adequately hydrate. Actual

hydration time is a function of site conditions and the form of bentonite used. Finely

divided forms of bentonite generally require less time for hydration, if properly mixed.

Dry bentonite peilets or chips may be placed directly into the annular space below water,

where a short section of annular space, up to 10 feet in length, is to be sealed. Care shall

be taken to prevent bridging during the placement of bentonite seal material.

(F) Radial Thickness of Seal. A minimum of two inches of sealing material shall be maintained

between all casings and the borehole wall, within the interval to be sealed, except where temporary

conductor casing cannot be removed, as noted in Subsection B of this Section. A minimum of two

inches of sealing material shall also be maintained between each casing, such as permanent

conductor casing, well casing, gravel fill pipes, etc., in a borehole within the interval to be sealed,

unless otherwise approved by the enforcing agency. Additional space shall be provided, where

needed, for casings to be properly centralized and spaced and allow the use of a tremie pipe during

well construction (if required), especially for deeper wells.

(F) Placement of Seal.

(1) Obstructions. All loose cuttings, or other obstructions to sealing shall be removed from

the annular space before placement of the annular seal.

(2) Centralizers. Well casing shall be equipped with centering guides or 'centralizers' to

ensure the 2-inch minimum radial thickness of the annular seal is at least maintained.

Centralizers need not be used in cases where the well casing is centered in the borehole

during well construction by use of removable tools, such as hollow-stem augers.

The spacing of centralizers is normally dictated by the casing materials used, the

orientation and straightness of the borehole, and the method used to install the casing.

Centralizers shall be metal, plastic, or other non-degradable material. Wood shall not be

used as a centralizer material. Centralizers must be positioned to allow the proper

placement of sealing material around casing within the interval to be sealed.

Any metallic component of a centralizer used with metallic casing shall consist of the same

material as the casing. Metallic centralizer components shall meet the same metallurgical

specifications and standards as the metallic casing to reduce the potential for galvanic

corrosion of the casing.

(3) Foundation and Transition Seals. A packer or similar retaining device, or a small

quantity of sealant that is allowed to set, can be placed at the bottom of the interval to be

sealed before final sealing operations begin to form a foundation for the seal.

A transition seal, up to 5 feet in length, consisting of bentonite, is sometimes placed in the

annular space to separate filter pack and cement-based sealing materials. The transition

seal can prevent cement-based sealing materials from infiltrating the filter pack. A short

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interval of fine-grained sand, usually less than 2 feet in length, is sometimes placed

between the filter pack and the bentonite transition seal to prevent bentonite from entering

the filter pack. Also, fine sand is sometimes used in place of bentonite as the transition seal

material.

Fine-sized forms of bentonite, such as granules and powder, are usually employed for

transition seals if a transition seal is to be placed above the water level in a well boring.

Coarse forms of bentonite, such as pellets and chips, are often used where a bentonite

transition seal is to be placed below the water level.

Transition seals should be installed by use of a tremie pipe, or equivalent. However, some

forms of bentonite may tend to bridge or clog in a tremie pipe.

Bentonite can be placed in dry form or as slurry for use in transition seals. Water should

be added to the bentonite transition seal prior to the placement of cement-based sealing

materials where bentonite is dry in the borehole. Care should be exercised during the

addition of water to the borehole to prevent displacing the bentonite.

Water should be added to bentonite at a ratio of about 1 gallon for every 2 pounds of

bentonite to allow for proper hydration. Water added to bentonite for hydration shall be of

suitable quality and free of pollutants and contaminants.

Sufficient time should be allowed for bentonite transition seals to properly hydrate before

cement-based sealing materials are placed. Normally, % to | hour is required for proper

hydration to occur. Actual time of hydration is a function of site conditions.

The top of the transition seal shall be sounded to ensure that no bridging has occurred

during placement.

(4) Timing and Method of Placement. The annular space shall be sealed as soon as practical

after completion of drilling or a stage of drilling. In no case shall the annular space be left

unsealed longer than 14 days following the installation of casing.

Sealing material shall be placed in one continuous operation from the bottom of the interval

to be sealed, to the top of the interval. Where the seal is more than 100 feet in length, the

deepest portion of the seal may be installed first and allowed to set or partially set. The

deep initial seal shall be no longer than 10 feet in length. The remainder of the seal shall

be placed above the initial segment in one continuous operation.

Sealing material shall be placed by methods (such as the use of a tremie pipe or equivalent)

that prevent freefall, bridging, or dilution of the sealing material, or separation of sand or

aggregate from the sealing material. Annular sealing materials shall not be installed by

freefall unless the interval to be sealed is dry and no deeper than 30 feet below ground

surface.

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(5) Groundwater Flow. Special care shall be used to restrict the flow of groundwater into

a well boring while placing material, where subsurface pressure causing the flow of water

is significant.

(6) Verification. It shall be verified that the volume of sealing material placed at least equals

or exceeds the volume to be sealed.

(7) Pressure. Pressure required for placement of sealing materials shall be maintained long

enough for cement-based sealing materials to properly set.

SECTION 10. Surface Construction Features

(A) Openings. Openings into the top of the well which are designed to provide access to the well,

i.e., for measuring, chlorinating, adding gravel, etc., shall be protected against entrance of surface

waters or foreign matter by installation of watertight caps or plugs. Access openings designed to

permit the entrance or egress of air or gas (air or casing vents) shall terminate above the ground

and above known flood levels and shall be protected against the entrance of foreign material by

installation of down-turned and screened "U" bends .

All other openings (holes, crevices, cracks, etc.) shall be sealed.

A "sounding tube" tap hole with plug, or similar access for the introduction of water level

measuring devices shall be affixed to the casing of all wells. For wells fitted with a "well cap" the

cap shall have a removable plug for this purpose.

(1) Where the pump is installed direct over the casing, a watertight seal (gasket) shall be

placed between the pump head and the pump base (slab), or a water-tight seal (gasket) shall

be placed between the pump base and the rim of the casing, or a "well cap" shall be installed

to close the annular opening between the casing and the pump column pipe.

(2) Where the pump is offset from the well or where a submersible pump is used, the

opening between the well casing and any pipes or cables which enter the well shall be

closed by a watertight seal or "well cap".

(3) If the pump is not installed immediately or if there is a prolonged interruption in

construction of the well, a watertight cover shall be installed at the top of the casing.

(4) A watertight seal or gasket shall be placed between the pump discharge head and the

discharge line; or, in the event of a below-ground discharge, between the discharge pipe

and discharge line.

(5) Bases. A concrete base or pad, sometimes called a pump block or pump pedestal, shall

be constructed at ground surface around the top of the well casing and contact the annular

seal, unless the top of the casing is below ground surface, as provided by Subsection B,

below.

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The base shall be free of cracks, voids, or other significant defects likely to prevent water

tightness. Contacts between the base and the annular seal, and the base and the well casing,

must be water tight and must not cause the failure of the annular seal or well casing. Where

cement-based annular sealing material is used, the concrete base shall be poured before the

annular seal has set, unless otherwise approved by the DEP.

The upper surface of the base shall slope away from the well casing. The base shall extend

at least two feet laterally in all directions from the outside of the well boring, unless

otherwise approved by the DEP. The base shall be a minimum of 4 inches thick.

A minimum base thickness of 4 inches is normally acceptable for small diameter, singleuser domestic wells. The base thickness should be increased for larger wells. Shape and

design requirements for well pump bases vary with the size, weight, and type of pumping

equipment to be installed, engineering properties of the soil on which the base is to be

placed, and local environmental conditions. A large variety of base designs have been used.

The Vertical Turbine Pump Association has developed a standard base design for large line

shaft turbine pumps. This design consists of a square, concrete pump base whose design is

dependent on bearing weight and site soil characteristics.

Where freezing conditions require the use of a pitless adapter, and the well casing and

annular seal do not extend above ground surface or into a pit or vault, a concrete base or

pad shall be constructed as a permanent location monument for the covered well. The base

shall be 3 feet in length on each side and 4 inches in thickness, unless otherwise approved

by the DEP. The base shall have a lift-out section, or equivalent, to allow access to the

well. The lift-out shall facilitate inspection and repair of the well.

(6) Where the well is to be gravel packed and the pack extends to the surface, a watertight

cover shall be installed between the conductor casing and the inner casing (see also Section

9, Subsection B, Item 5).

(B) Well Pits or Vaults. The use of well pits, vaults, or equivalent features to house the top of a

well casing below ground surface shall be avoided, if possible, because of their susceptibility to

the entrance of poor-quality water, contaminants and pollutants. Well pits or vaults can only be

used if approval is obtained from the DEP. A substitute device, such as a pitless adapter or pitless

adapter unit (a variation), should almost always be used in place of a vault or pit.

Pitless adapters and units were developed for use in areas where prolonged freezing occurs, and

below ground (frost line) discharges are common. Both the National Sanitation Foundation and

Water Systems Council have developed standards for the manufacture and installation of pitless

adapters and units.

If a pit or vault is used it shall be watertight and structurally sound. The vault shall extend from

the top of the annular seal to at least ground surface.

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The vault shall contact the annular seal in a manner to form a watertight and structurally sound

connection. Contacts between the vault and the annular seal, and the vault and the well casing, if

any, shall not fail or cause the failure of the well casing or annular seal.

Where cement-based annular seal materials are used, the vault shall be set into or contact the

annular seal material before it sets, unless otherwise approved by the DEP. If bentonite-based

sealing material is used for the annular seal, the vault should be set into the bentonite before it is

fully hydrated.

Cement-based sealing material shall be placed between the outer wails of the vault and the

excavation into which it is placed to form a proper, structurally sound foundation for the vault, and

to seal the space between the vault and excavation.

The sealing material surrounding a vault shall extend from the top of the annular seal to ground

surface unless precluded in areas of freezing. If cement-based sealing material is used for both the

annular seal and the space between the excavation and vault, the sealing material shall be emplaced

in a ‘continuous pour’. In other words, cement-based sealing material shall be placed between the

vault and excavation and contact the cement-based annular seal before the annular seal has set.

The vault cover or lid shall be watertight but shall allow the venting of gases. The lid shall be fitted

with a security device to prevent unauthorized access. The outside of the lid shall be clearly and

permanently labeled 'WATER WELL’. The vault and its lid shall be strong enough to support

vehicular traffic where such traffic might occur.

The top of the vault shall be set at, or above, grade so that drainage is away from the vault. The

top of the well casing contained within the vault shall be covered in accordance with requirements

under Subsection A, above, so that water, contaminants, and pollutants that may enter the vault

will not enter the well casing. The cover shall be provided with a pressure relief or venting device

for gases.

shall be located in a locked enclosure to exclude access by unauthorized persons.

(D) Pump Blowoff. When there is a blowoff or drain line from the pump discharge, it shall be

located above any known flood levels and protected against the possibility of back siphonage or

backpressure. The blowoff or drain line shall not be connected to any sewer or storm drain except

when connected through an air gap.

(E) Air Vents. In community water supply wells to minimize the possibility of contamination

caused by the creation of a partial vacuum during pumping, a casing vent shall be installed . In

addition, to release air trapped in the pump column when the pump is not running, air release vents

shall be installed. Air vents are also recommended for other types of wells except those having jet

pump installations requiring positive pressure (which cannot have a vent).

(F) Backflow Prevention. All pump discharge pipes not discharging or open to the atmosphere

shall be equipped with an automatic device to prevent backflow and/or back siphonage into a well.

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Specific backflow preventers shall have passed laboratory and field evaluation tests performed by

a Federally recognized testing organization. Specific backflow prevention measures are required

for drinking water supply wells as prescribed below.

(1) Construction of backflow preventers

(a) Air-gap Separation. An Air-gap separation (AG) shall be at least double the

diameter of the supply pipe, measured vertically from the flood rim of the receiving

vessel to the supply pipe; however, in no case shall this separation be less than one

inch.

(b) Double Check Valve Assembly. A required double check valve assembly (DC)

shall, as a minimum, conform to the AWWA Standard C506-78 (R83) for Double

Check Valve Type Backflow Preventive Devices.

pressure principle backflow prevention device (RP) shall, as a minimum, conform

to the AWWA Standard C506-78 (R83) for Reduced Pressure Principle Type

Backflow Prevention Devices.

(2) Location of Backflow Preventers

(a) Air-gap Separation. An air-gap separation shall be located as close as practical

to the user's connection and all piping between the user's connection and the

receiving tank shall be entirely visible unless otherwise approved in writing by the

water supplier and the health agency.

(b) Double Check Valve Assembly. A double check valve assembly shall be located

as close as practical to the user's connection and shall be installed above grade, if

possible, and in a manner where it is readily accessible for testing and maintenance.

principle backflow prevention device shall be located as close as practical to the

user's connection and shall be installed a minimum of twelve inches (12 ") above

grade and not more than thirty-six inches (36 ") above grade measured from the

bottom of the device and with a minimum of twelve inches (12 ") side clearance.

(3) Type of Backflow Protection Required

Sewage and Hazardous Substances

(a) Premises where there are waste water pumping and/or treatment plants and there

is no interconnection with the potable water system. This does not include a singlefamily residence that has a sewage lift pump. An AG is required, but a RP maybe

provided in lieu of an AG if approved by the health agency and water supplier.

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(b) Premises where hazardous materials are handled in any manner in which the

substances may enter the potable water system. This does not include a singlefamily residence that has a sewage lift pump. An AG is required but a RP may be

provided in lieu of an AG if approved by the health agency and water supplier.

pesticides are, or can be, injected. RG required.

Auxiliary Water Supplies

(a) Premises where there is an unapproved auxiliary water supply, which Is

interconnected with the public water system. An AP is required. A RP or DC may

be provided in lieu of an AG if approved by the health agency and water supplier.

(b) Premises where there is an unapproved auxiliary water supply and there are no

interconnections with the public water system. An RP is required, and a DC may

be provided in lieu of a RP I approved by the health agency and the water supplier.

Recycled water

(a) Premises where the public water system is used to supplement the recycled

water supply, an AG is required.

(b) Premises where recycled water is used, other than as_ allowed in paragraph (c)

below, and there is no interconnection with the potable water system, an RP is

required

dual plumbed use area require the use of a DC. If the water supplier is also the

supplier of the recycled water, an alternative backflow protection plan that includes

an annual inspection an annual shutdown test of the recycled water and potable

water systems.

Fire Protection Systems

(a) Premises where the fire system is directly supplied from the public water system

and there is an unapproved auxiliary water supply on or to the premises (not

interconnected), a DC is required

(b) Premises where the fire system is supplied from the public water system and

interconnected with an unapproved auxiliary water supply, an AG is required. A

RP may be provided in lieu of an AG if approve by health agency and water

supplier.

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where either elevated storage tanks or fire pumps which take suction from private

reservoirs or tanks are used, a DC is required.

(d) Buildings where the fire system is supplied from the public water system and

where recycled water is used in a separate piping system within the same building,

a DC is required.

Dockside watering points and marine facilities

(a) Pier hydrants for supplying water to vessels for any purpose require an RP.

(b) Premises where there are marine facilities, an RP is required.

Premises where entry is restricted so that inspections for cross connections cannot

be made with sufficient frequency or at sufficiently short notice to ensure that they

do not exist, and RP is required

Premises where there is a repeated history of cross-connections being established

or re-established, an RP is required.

(4) Testing and Maintenance of Backflow Preventors

(a) The water supplier shall assure that adequate maintenance and periodic testing

are provided by the water user to ensure their proper operation.

(b) Backflow preventers shall be tested by persons who have demonstrated their

competency in testing of these devices to the water supplier or health agency.

determined to be necessary by the health agency or water supplier. When devices

are found to be defective, they shall be repaired or replaced in accordance with the

provisions of this Chapter.

(d) Backflow preventers shall be tested immediately after they are installed,

relocated or repaired and not placed in service unless they are functioning as

required.

(e) The water supplier shall notify the water user when testing of backflow

preventers is needed. The notice shall contain the date when the test must be

completed.

(f) Reports of testing and maintenance shall be maintained by the water supplier for

a minimum of three years.

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Irrigation well systems, including those used for landscape irrigation, and other well

systems that employ, or which have been modified to employ, chemical feeders or injectors

shall be equipped with a backflow prevention device(s) approved by the DEP.

SECTION 11. Disinfection and Other Sanitary Requirements

(A) Disinfection. All wells producing water for domestic use (i.e., drinking or food processing)

shall be disinfected following construction, repair, or when work is done on the pump, before the

well is placed in service.

(B) Gravel. Gravel used in gravel-packed wells shall come from clean sources and should be

thoroughly washed before being placed in the well. Gravel purchased from a supplier should be

washed at the pit or plant prior to delivery to the well site.

in tablet or granular form) shall be added to the gravel at a uniform rate (two tablets per cubic foot

or one pound of the granular form per cubic yard).

(D) Lubricants) Mud and water used as a drilling lubricant shall be free from sewage

contamination. Oil and water used for lubrication of the pump and pump bearing shall also be free

from contamination.

SECTION 12. Casing

(A) Casing Material. Requirements pertaining to well casing are to ensure that the casing will

perform the functions for which it is designed, i.e., to maintain the hole by preventing its walls

from collapsing, to provide a channel for the conveyance of the water, and to provide a measure

of protection for the quality of the water pumped.

(1) Well casing shall be strong and tough enough to resist the force imposed on it during

installation and those forces which can normally be expected after installation.

(2) Steel is the material most frequently used for well casing, especially in drilled wells.

The thickness of steel used for well casing shall be selected in accordance with good

design practices applied with due consideration to conditions at the site of the well.

There are three principal classifications of steel materials used for water well casing,

and all are acceptable for use so long as they meet the following conditions.

(a) Standard and line pipe. This material shall meet one of the following

specifications, including the latest revision thereof:

(i) API Std. 5L, "Specification for Line Pipe”.

(ii) API Std. SLX, "Specification for High-Test Line Pipe".

(iii) ASTM A53, "Standard Specification for Pipe, Steel, Black and

Hot-Dipped, Zinc-Coated Welded and Seamless".

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(iv) ASTM A120, "Standard Specification for Pipe, Steel, Black and

Hot-Dipped, Zinc-Coated (Galvanized) Welded and Seamless, for

Ordinary Uses".

(v) ASTM A134, "Standard Specification for Electric-Fusion (Arc)-

Welded Steel Pipe (sizes NPS 16 and over)".

(vi) ASTM A135, "Standard Specification for Electric-Resistance-

Welded Steel Pipe”.

(vii) ASTM A139, "Standard Specification for Electric-Fusion

(Arc)-Welded Steel Pipe (sizes 4 inches and over)".

(viii) ASTM A211, "Standard Specification for Spiral- Welded Steel

or Iron Pipe".

(ix) AWWA C200, "AWWA Standard for Steel Water Pipe 6 Inches

and Larger".

(b) Structural Steel. This material shall meet one of the following specifications of

the American Society for Testing and Materials, including the latest revision

thereof:

(i) ASTM A36, "Standard Specification for Structural Steel".

(ii) ASTM A242, "Standard Specification for High Strength Low

Alloy Structural Steel".

(ili) ASTM A283, "Standard Specification for Low and Intermediate

Tensile Strength Carbon Steel Plates of Structural Quality.

(iv) ASTM A441, "Tentative Specification for High-Strength Low

Alloy Structural Manganese Vanadium Steel".

(v) ASTM A570, "Standard Specification for Hot-Rolled Carbon

Steel Sheet and Strip, Structural Quality".

fabricators as "well casing steel". At present, there are no standard

specifications concerning this material. However, the major steel producers

market products whose chemical and physical properties are quite similar. Each

sheet of material shall contain mill markings which will identify the

manufacturer and specify that the material is well casing steel which complies

with the chemical and physical properties published by the manufacturer.

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(d) Stainless steel casing shall meet the provisions of ASTM A409, "Standard

Specification for Welded Large Diameter Austenitic Steel Pipe for Corrosive

or High Temperature Service".

(3) Plastic. Two basic types of plastic are commonly used for plastic well casing:

thermoplastics and thermosets. Thermoplastics soften with the application of heat and

reharden when cooled. Thermoplastics can be reformed repeatedly using heat and

sometimes can unexpectedly deform. Attention should be given to the effect of heat on

thermoplastic casing from the setting and curing of cement. Additional discussion on

sealing material and heat generation is in Section 9, Subsection E, ‘Sealing Material’.

Thermoplastics used for well casing include ABS (acrylonitrile butadiene styrene), PVC

(polyvinyl chloride), and SR (styrene rubber). PVC is the most frequently used

thermoplastic well casing in California. Styrene rubber is seldom used.

Unlike thermoplastics, thermoset plastics cannot be reformed after heating. The molecules

of thermoset plastic are ‘set’ during manufacturing by heat, chemical action, or a

combination of both. The thermoset plastic most commonly used for well casing is

fiberglass.

(a) Thermoplastics. Thermoplastic well casing shall meet the requirements of

ASTM F480. Standard Specification for Thermoplastic Well Casing Pipe and

Couplings Made in Standard Dimension Ratios (SDR), SCH 40 and SCH 80,

including the latest revision thereof. (Note: A ‘dimension ratio’ is the ratio of pipe

diameter to pipe wall thickness.)

Pipe made in Schedule 40 and 80 wall thicknesses and pipe designated according

to certain pressure classifications are listed in ASTM F480, as well as casing

specials referencing the following ASTM specifications:

(i) ABS Pipe. ASTM D1527, Standard Specification for Acrylonitrile-

Butadiene-Styrene (ABS) Plastic Pipe, Schedules 40 and 80.

(ii) PVC Pipe. ASTM D1785, Standard Specification for (Poly Vinyl

Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120.

(iit) Pressure-Rated PVC Pipe. ASTM D2241, Standard Specifications for

Poly (Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series).

Thermoplastic well casing that may be subject to significant impact stress

during or after installation shall meet or exceed the requirements for impact

resistance classification set forth in Section 6.5 of ASTM F480. Casing that

may be subject to significant impact forces includes, but is not limited to;

casing that is installed in large diameter, deep boreholes; and casing through

which drilling tools pass following installation of the casing in a borehole.

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(b) Thermoset_Plastics. Thermoset casing material shall meet the following

specifications, as applicable, including the latest revisions thereof:

(i) Filament Wound Resin Pipe. ASTM D2996, Standard Specification for

Filament Wound Reinforced Thermosetting Resin Pipe.

(ii) Centrifugally Cast Resin Pipe. ASTM D2997, Standard Specification

for Centrifugally Cast Reinforced Thermosetting Resin Pipe.

(iii) Reinforced Plastic Mortar Pressure Pipe. ASTM D3517, Standard

Specification for Reinforced Plastic Mortar Pressure Pipe.

(iv) Glass Fiber Reinforced Resin Pressure Pipe. AWWA C950, AWWA

Standards for Glass-Fiber-Reinforced Thermosetting-Resin Pressure Pipe.

including community supply well and individual domestic wells, shall meet the

provisions of National Sanitation Foundation Standard No. 14, Plastic Piping

Components and related Materials and any revision thereof. The casing shall be

marked or labeled following requirements in NSF Standard No. 14. Standard No.

14 includes the requirements of ASTM F480.

(d) Storage, Handling, and Transportation. Plastic casing shall not be stored in

direct sunlight or subjected to freezing temperatures for extended periods of time.

Plastic casing shall be stored, handled, and transported in a manner that prevents

excessive mechanical stress. Casing shall be protected from sagging and bending,

severe impacts and loads, and potentially harmful chemicals.

(e) Large Diameter Wells. Because large diameter plastic casing has not been used

extensively at depths exceeding 500 feet, special care shall be exercised with its use

in deep wells.

(4) Concrete pipe used for casing should conform to the following specifications, including

the latest revision thereof:

(a) ASTM C14, "Standard Specifications for Concrete Sewer, Storm Drain, and

Culvert Pipe".

(b) ASTM C76, "Standard Specifications for Reinforced Concrete Sewer, Storm

Drain, and Culvert Pipe".

Cylinder Type, for Water and Other Liquids".

(d) AWWA C301, "AWWA Standard for Prestressed Concrete Pressure Pipe Steel,

Cylinder Type, for Water and Other Liquids”.

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(5) Unacceptable Casing Materials. Galvanized sheet metal pipe such as 'downspout' tile

pipe, or natural wood shall not be used as well casing.

(6) Other Materials. Materials in addition to those described above may be used as well

casing, subject to enforcing agency approval.

(B) Casing Installation. All well casing shall be assembled and installed with sufficient care to

prevent damage to casing sections and joints. All casing joints above intervals if perforations or

screen shall be watertight. Any perforations shall be below the depths specified in Section 9,

Subsection A, of this Chapter.

Casing shall be equipped with centering guides or 'centralizers' to ensure the even radial thickness

of the annular seal and filter pack.

(1) Metal Casing. Metallic casing may be joined by welds, threads, or threaded couplings.

Welding shall be accomplished in accordance with the standards of the American Welding

Society or the most recent revision of the American Society of Mechanical Engineers

Boiler Construction Code. Metallic casing shall be equipped with a ‘drive shoe' at the lower

end if it is driven into place.

(2) Plastic Casing. Plastic casing may be joined by solvent welding or mechanically joined

by threads or other means, depending on the type of material and its fabrication. Solvent

cement used for solvent welding shall meet specifications for the type of plastic casing

used. Solvent cement shall be applied in accordance with solvent and casing manufacturer

instructions. Particular attention shall be given to instructions pertaining to required setting

time for joints to develop strength.

The following specifications for solvent cements and joints for PVC casing shall be met,

including the latest revisions thereof:

(a) ASTM D2564, Standard Specification for Solvent Cements for Poly (Vinyl

Chloride) (PVC) Plastic Pipe and Fittings.

(b) ASTM D2855, Standard Practice for Making Solvent-Cemented Joints with Poly

(Vinyl Chloride) (PVC) Pipe and Fittings.

Plastic casing or screen shall not be subjected to excessive stress during installation and

shall not be driven into place. Care shall be taken to ensure that plastic casing and joints

are not subjected to excessive heat from cement-based sealing material.

A specifically designed adapter shall be used to join plastic casing to metallic casing or

screen.

SECTION 13. Sealing-off Strata

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In areas where a well penetrates more than one aquifer, and one or more of the aquifers contains

water that, if allowed to mix in sufficient quantity, will result in a significant deterioration of the

quality of water in the other aquifer(s) or the quality of water produced, the strata producing such

poor-quality water shall be sealed off to prevent entrance of the water into the well or its migration

to other aquifer(s).

(A) Strata producing the undesirable quality water shall be sealed off by placing impervious

material opposite the strata and opposite the confining formation(s). The seal shall extend above

and below the strata no less than 10 feet even should the confining formation be less than 10 feet

in thickness. In the case of "bottom" waters, the seal shall extend 10 feet in the upward direction.

The sealing material shall fill the annular space between the casing and the wall of the drilled hole

in the interval to be sealed, and the surrounding void spaces which might absorb the sealing

material. The sealing material shall be placed from the bottom to the top of the interval to be sealed.

In areas where deep subsidence may occur provision shall be made for maintaining the integrity

of the annular seal in the event of subsidence. Such preventive measures may include the

installation of a "sleeve" or "slip joint" in the casing, which will allow vertical movement in the

casing without its collapse.

(B) Sealing material shall consist of neat cement, cement grout, or bentonite clay (see Section 9,

Subsection E for description of the various materials).

SECTION 14. Well Development

Development, redevelopment, or reconditioning of a well shall be performed with care, by method

that will not damage the well structure or destroy natural barriers to the movement of poor-quality

water, pollutants, and contaminants.

Acceptable well development, redevelopment, or reconditioning methods include:

Over pumping;

Surging or swabbing by use of 'plungers’;

Surging with compressed air;

Backwashing or surging by alternately starting and stopping a pump;

Jetting with water;

Introducing specifically-formulated chemicals into a well; and,

Combinations of the above.

Hydraulic fracturing (hydrofracturing) is sometimes an acceptable well development and

redevelopment method when properly performed. Good quality water shall be used in

hydrofracturing. The water shall be disinfected prior to introduction into a well. Material used as

'propping' agents shall be free of pollutants and contaminants, shall be compatible with the use of

a well, and shall be thoroughly washed and disinfected prior to placement in a well.

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Development, redevelopment, or reconditioning by use of specially designed explosive charges is

in some cases, another acceptable development method. Explosives shall be used with special care

to prevent damage to the well structure and to any natural barriers to the movement of poor-quality

water, pollutants, and contaminants. Explosives shall only be used by properly- trained personnel.

Wells subjected to chemicals or explosives during development, redevelopment, or reconditioning

operations shall be thoroughly pumped to remove such agents and residues immediately after the

completion of operations. Chemicals, water, and other wastes removed from the well shall be

disposed of in accordance with applicable local, State, and federal requirements. The DEP should

be contacted regarding the proper disposal of waste.

SECTION 15. Water Quality Sampling

The requirements to be followed with respect to water quality sampling are:

(A) Community Water Supply Wells and Certain Industrial Wells. The water from all community

water supply wells and industrial wells which provide water for use in food processing shall be

sampled immediately following development and disinfection, and appropriate analysis made.

Rules and regulations governing the constituents to be tested, type of testing, etc., for community

water supply systems are regulated and enforced by the Tribe and USEPA through the Public

Water System Supervision (PWWS) program. Currently regulated contaminants, potential health

effects, and sources of contaminants can be found in the USEPA National Primary Drinking Water

Standards, which lists the legally enforceable standards that apply to public water systems as well

as National Secondary Drinking Water Regulations, the non-enforceable guidelines regulating

contaminants that may cause cosmetic or aesthetic effects in drinking water. Water analysis shall

be performed by a laboratory certified by an accredited laboratory. The laboratory should be able

to provide a valid Environmental laboratory Accreditation program or National laboratory

accreditation program number. A copy of the laboratory analysis shall be forwarded to the DEP

and USEPA. Approval of the EPA must be obtained before the well is put into use.

Except where there is free discharge from the pump (that is, there is no direct connection to the

water delivery system such as to a sump), a sample tap (see Figure 7) shall be provided on the

discharge line so that water representative of the water in the well may be drawn for laboratory

analysis. The tap shall be located so as to prevent back siphonage to the pump discharge when the

pump is shut off (e.g., on the system side of the check valve).

(B) Other Types of Wells. To determine the quality of water produced by a new well it should be

sampled immediately following construction and development. Appropriate analyses shall be

made based upon the intended uses of the water.

SECTION 16. Special Provisions for Large Diameter Shallow Wells

(A) Use as Community Water Supply Wells. Because shallow groundwaters are often of poor

quality and because they are easily contaminated, the use of bored or dug wells, or wells less than

50 feet deep, to provide community water supplies shall be avoided (unless there is no other

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feasible means for obtaining water). When used for this purpose, these wells shall be located at

least 2,000 feet from any underground sewage disposal facility.

(B) Bored Wells. All bored wells shall be cased with concrete pipe or steel casing whose joints are

water-tight from 6 inches above the ground surface to the depths specified in Section 9, Subsection

A of this Chapter. Except where corrugated steel pipe is used as casing, the minimum thickness of

the surrounding concrete seal shall be 3 inches. Where corrugated steel pipe is employed, the joints

are not watertight and a thicker annular seal (no less than 6 inches) shall be installed.

the ground surface to the depths specified in Section 9, Subsection A of this Chapter. The curbing

shall be of concrete poured-in-place or of casing (either precast concrete pipe or steel) surrounded

on the outside by concrete.

If the curbing is to be made of concrete, poured-in-place, it shall not be less than 6 inches thick. If

precast concrete pipe or steel casing is used as part of the curbing, the space between the wall of

the hole and the casing shall be filled with concrete to the depths specified in Section 9, Subsection

A of this Chapter. The minimum thickness of the surrounding concrete shall be 3 inches.

(D) Casing Material. Either steel (including corrugated steel pipe) or concrete may be used for

casing bored or dug wells. Corrugated aluminum pipe is not recommended for use as casing.

(1) Steel used in the manufacture of casing for bored and dug wells should conform to the

specifications for casing material described in Section 12. Minimum thickness of steel

casing for bored and dug wells shall be:

U.S. Standard Gage

Diameter (inches) or Plate Thickness

18 8 gage

24 1/4 inch

30 1/4 inch

36 1/4 inch

42 1/4 inch

48 1/4 inch

(2) Corrugated steel pipe used as casing shall meet the specifications (including the latest

revision) of ASTM A444, "Standard Specification for Steel Sheet, Zinc Coated

(Galvanized) by the HOT-DIP Process for Culverts and Under- drains". The minimum

thickness of sheet used shall be 0.109 inch.

(3) Concrete casing can consist of either poured-in-place concrete or precast concrete pipe.

Poured-in-place concrete should be sufficiently strong to withstand the earth and water

pressures imposed on it during, as well as after, construction. It should be properly

reinforced with steel to furnish tensile strength and to resist cracking, and it should be free

from honeycombing or other defects likely to impair the ability of the concrete structure to

remain watertight. Aggregate small enough to place without "bridging" should be used.

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Poured-in-place concrete shall be "Class A" (6 sacks of Portland cement per cubic yard) or

"Class B" (5 sacks per cubic yard).

Precast concrete pipe is usually composed of concrete rings from 1 to 6 feet in diameter

and approximately 3 to 8 feet long. To serve satisfactorily as casing, these rings should be

free of blemishes that would impair their strength or serviceability. Concrete pipe shall

conform to the specifications listed in Section 12, Subsection A, Item 4.

(E) Covers. All bored and dug wells shall be provided with a structurally sound, watertight, cover

made of concrete or steel.

SECTION 17. Special Provisions for Driven Wells ("Well Points")

(A) If the well is to be used as an individual domestic well, an oversize hole with a diameter at

least 3 inches greater than the diameter of the pipe shall be constructed to a depth of 6 feet and the

annular space around the pipe shall be filled with neat cement, cement grout, or bentonite mud.

(B) The minimum wall thickness of steel drive pipe shall not be less than 0.140 inch.

place.

SECTION 18. Rehabilitation, Repair, and Deepening of Wells

(A) Rehabilitation is the treatment of a well by chemical or mechanical means (or both) to recover

lost production caused by incrustation or clogging of screens or the formation immediately

adjacent to the well. The following methods used for rehabilitating a well when done with care are

acceptable: (1) introduction of chemicals designed for this purpose, (2) surging by use of

compressed air, (3) backwashing or surging by alternately starting or stopping the pump, (4) jetting

with water, (5) sonic cleaning, (6) vibratory explosives, and (7) combinations of these. Methods

which produce an explosion (in addition to the use of vibratory explosives mentioned above) are

also acceptable provided, however, they are used with great care, particularly where aquifers are

separated by distinct barriers to the movement of groundwater.

In those cases where chemicals or explosives have been used, the well shall be pumped until all

traces of them have been removed.

(B) In the repair of wells, material used for casing shall meet the requirements of Section 12

"Casing" of these provisions. In addition, the requirements of this Chapter set forth in Section 11,

Subsection A "Disinfection" and, when applicable, Section 13 "Sealing-off Strata" shall be

followed.

Section 14, and Section 15 of this Chapter shall be followed.

SECTION 19. Temporary Cover

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This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.