# 35 Ill. Adm. Code 6110.611.311: Section 611.311 MCLs for Organic Chemical Contaminants

> Illinois · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/STATE_IL_IAC_T35_P6110_S611_311

## Section

- **Citation:** 35 Ill. Adm. Code 6110.611.311
- **Heading:** Section 611.311 MCLs for Organic Chemical Contaminants
- **Jurisdiction:** Illinois
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Illinois Administrative Code / Title 35  /  / Part 6110  / Section 611.311 MCLs for Organic Chemical Contaminants

## Text

Section 611
TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE F: PUBLIC WATER SUPPLIES
CHAPTER I: POLLUTION CONTROL BOARD
PART 611 PRIMARY DRINKING WATER STANDARDS
SECTION 611.311 MCLS FOR ORGANIC CHEMICAL CONTAMINANTS
Section 611.311  MCLs for
Organic Chemical Contaminants
a)         Maximum Contaminant Levels for Volatile Organic Chemical
Contaminants. The MCLs for VOCs apply to CWS suppliers and NTNCWS suppliers:
CAS No.
Contaminant
MCL (mg/L)
71-43-2
Benzene
0.005
56-23-5
Carbon tetrachloride
0.005
95-50-1
o-Dichlorobenzene
0.6
106-46-7
p-Dichlorobenzene
0.075
107-06-2
1,2-Dichloroethane
0.005
75-35-4
1,1-Dichloroethylene
0.007
156-59-2
cis-1,2-Dichloroethylene
0.07
156-60-5
trans-1,2-Dichloroethylene
0.1
75-09-2
Dichloromethane (methylene
chloride)
0.005
78-87-5
1,2-Dichloropropane
0.005
100-41-4
Ethylbenzene
0.7
108-90-7
Monochlorobenzene
0.1
100-42-5
Styrene
0.1
127-18-4
Tetrachloroethylene
0.005
108-88-3
Toluene
1
120-82-1
1,2,4-Trichlorobenzene
0.07
71-55-6
1,1,1-Trichloroethane
0.2
79-00-5
1,1,2-Trichloroethane
0.005
79-01-6
Trichloroethylene
0.005
75-01-4
Vinyl chloride
0.002
1330-20-7
Xylenes (total)
10
b)         USEPA, under section 1412 of SDWA identifies in this
subsection (b) granular activated carbon (GAC), packed tower aeration (PTA), or
oxidation (OX) as BAT, treatment technique, or other means available for
achieving compliance with the MCLs for VOCs, and SOCs in subsections (a) and
(c) except for per-and polyfluoroalkyl substances (PFAS), as indicated:
CAS No
20-7
Xylenes (total)
10
b)         USEPA, under section 1412 of SDWA identifies in this
subsection (b) granular activated carbon (GAC), packed tower aeration (PTA), or
oxidation (OX) as BAT, treatment technique, or other means available for
achieving compliance with the MCLs for VOCs, and SOCs in subsections (a) and
(c) except for per-and polyfluoroalkyl substances (PFAS), as indicated:
CAS No.
Contaminant
BAT
15972-60-8
Alachlor
GAC
116-06-3
Aldicarb*
GAC
1646-87-4
Aldicarb sulfone*
GAC
1646-87-3
Aldicarb sulfoxide*
GAC
1912-24-9
Atrazine
GAC
71-43-2
Benzene
GAC, PTA
50-32-8
Benzo(a)pyrene
GAC
1563-66-2
Carbofuran
GAC
56-23-5
Carbon tetrachloride
GAC, PTA
57-74-9
Chlordane
GAC
94-75-7
2,4-D
GAC
75-99-0
Dalapon
GAC
96-12-8
Dibromochloropropane
GAC, PTA
95-50-1
o-Dichlorobenzene
GAC, PTA
106-46-7
p-Dichlorobenzene
GAC, PTA
107-06-2
1,2-Dichloroethane
GAC, PTA
156-59-2
cis-1,2-Dichloroethylene
GAC, PTA
156-60-5
trans-1,2-Dichoroethylene
GAC, PTA
75-35-4
1,1-Dichloroethylene
GAC, PTA
75-09-2
Dichloromethane
PTA
78-87-5
1,2-Dichloropropane
GAC, PTA
103-23-1
Di(2-ethylhexyl)adipate
GAC, PTA
117-81-7
Di(2-ethylhexyl)phthalate
GAC
88-85-7
Dinoseb
GAC
85-00-7
Diquat
GAC
145-73-3
Endothall
GAC
72-20-8
Endrin
GAC
106-93-4
Ethylene dibromide (EDB)
GAC, PTA
100-41-4
Ethylbenzene
GAC, PTA
1071-53-6
Glyphosate
OX
76-44-8
Heptachlor
GAC
1024-57-3
Heptachlor epoxide
GAC
118-74-1
Hexachlorobenzene
GAC
77-47-3
Hexachlorocyclopentadiene
GAC, PTA
58-89-9
Lindane
GAC
72-43-5
Methoxychlor
GAC
108-90-7
Monochlorobenzene
GAC, PTA
23135-22-0
Oxamyl
GAC
87-86-5
Pentachlorophenol
GAC
1918-02-1
Picloram
GAC
1336-36-3
Polychlorinated biphenyls
(PCB)
GAC
122-34-9
Simazine
GAC
100-42-5
Styrene
GAC, PTA
1746-01-6
2,3,7,8-TCDD
GAC
127-18-4
Tetrachloroethylene
GAC, PTA
108-88-3
Toluene
GAC, PTA
8001-35-2
Toxaphene
GAC
120-82-1
1,2,4-trichlorobenzene
GAC, PTA
71-55-6
1,1,1-Trichloroethane
GAC, PTA
79-00-5
1,1,2-trichloroethane
GAC, PTA
79-01-6
Trichloroethylene
GAC, PTA
93-72-1
2,4,5-TP
GAC
75-01-4
Vinyl chloride
PTA
1330-20-7
Xylene
GAC, PTA
(PCB)
GAC
122-34-9
Simazine
GAC
100-42-5
Styrene
GAC, PTA
1746-01-6
2,3,7,8-TCDD
GAC
127-18-4
Tetrachloroethylene
GAC, PTA
108-88-3
Toluene
GAC, PTA
8001-35-2
Toxaphene
GAC
120-82-1
1,2,4-trichlorobenzene
GAC, PTA
71-55-6
1,1,1-Trichloroethane
GAC, PTA
79-00-5
1,1,2-trichloroethane
GAC, PTA
79-01-6
Trichloroethylene
GAC, PTA
93-72-1
2,4,5-TP
GAC
75-01-4
Vinyl chloride
PTA
1330-20-7
Xylene
GAC, PTA
*See the Board
note at the end of this Section.
c)         The following maximum contaminant levels (MCLs) in Tables 1
and 2 to subsection (c) for synthetic organic contaminants apply to CWS and NTNCWS
suppliers; Table 2 also contains health-based water concentrations (HBWCs) for
selected per-and poly-fluoroalkyl substances (PFAS) used in calculating the
Hazard Index.
1)         MCLs for SOCs (except for PFAS) apply to CWS and NTNCWS
suppliers:
CAS Number
Contaminant
MCL (mg/L)
15972-60-8
Alachlor
0.002
116-06-3
Aldicarb*
0.003
1646-87-4
Aldicarb sulfone*
0.002
1646-87-3
Aldicarb sulfoxide*
0.004
1912-24-9
Atrazine
0.003
50-32-8
Benzo(a)pyrene
0.0002
1563-66-2
Carbofuran
0.04
57-74-9
Chlordane
0.002
94-75-7
2,4-D
0.07
75-99-0
Dalapon
0.2
96-12-8
Dibromochloropropane
0.0002
103-23-1
Di(2-ethylhexyl)adipate
0.4
117-81-7
Di(2-ethylhexyl)phthalate
0.006
88-85-7
Dinoseb
0.007
85-00-7
Diquat
0.02
145-73-3
Endothall
0.1
72-20-8
Endrin
0.002
106-93-4
Ethylene dibromide
0.00005
1071-53-6
Glyphosate
0.7
76-44-8
Heptachlor
0.0004
1024-57-3
Heptachlor epoxide
0.0002
118-74-1
Hexachlorobenzene
0.001
77-47-4
Hexachlorocyclopentadiene
0.05
58-89-9
Lindane
0.0002
72-43-5
Methoxychlor
0.04
23135-22-0
Oxamyl (Vydate)
0.2
87-86-5
Pentachlorophenol
0.001
1918-02-1
Picloram
0.5
1336-36-3
Polychlorinated biphenyls (PCBs)
0.0005
122-34-9
Simazine
0.004
1746-01-6
2,3,7,8-TCDD (Dioxin)
0.00000003
8001-35-2
Toxaphene
0.003
93-72-1
2,4,5-TP
0.05
* See the Board note at the end of this Section
benzene
0.001
77-47-4
Hexachlorocyclopentadiene
0.05
58-89-9
Lindane
0.0002
72-43-5
Methoxychlor
0.04
23135-22-0
Oxamyl (Vydate)
0.2
87-86-5
Pentachlorophenol
0.001
1918-02-1
Picloram
0.5
1336-36-3
Polychlorinated biphenyls (PCBs)
0.0005
122-34-9
Simazine
0.004
1746-01-6
2,3,7,8-TCDD (Dioxin)
0.00000003
8001-35-2
Toxaphene
0.003
93-72-1
2,4,5-TP
0.05
* See the Board note at the end of this Section.
2)         MCLs and HBWCs for PFAS apply to CWS and NTNCWS suppliers:
CAS Number
Contaminant
MCL (mg/ L)
HBWC (mg/l)
Not applicable
Hazard Index PFAS
(HFPO-DA, PFBS, PFHxS, and PFNA)
1 (unitless)
1
Not applicable
122499-17-6
HFPO-DA
0.00001
0.00001
45187-15-3
PFBS
No Individual MCL
0.002
108427-53-8
PFHxS
0.00001
0.00001
72007-68-2
PFNA
0.00001
0.00001
45285-51-6
PFOA
0.0000040
Not applicable
45298-90-6
PFOS
0.0000040
Not applicable
1
The PFAS Mixture
Hazard Index (HI) is the sum of component hazard quotients (HQs), which are
calculated by dividing the measured component PFAS concentration in water by
the relevant health-based water concentration when expressed in the same units
(shown in ng/l for simplification). The HBWC for PFHxS is 10 ng/l; the HBWC for
HFPO-DA is 10 ng/l; the HBWC for PFNA is 10 ng/l; and the HBWC for PFBS is 2000
ng/l.  A PFAS Mixture Hazard Index greater than 1 (unitless) indicates an
exceedance of the health protective level and indicates potential human health
risk from the PFAS mixture in drinking water.
Hazard Index = ([HFPO-DA
water
ng/l]/[10 ng/l]) + ([PFBS
water
ng/l]/[2000 ng/l]) + ([PFNA
water
ng/l]/[10 ng/l]) + ([PFHxS
water
ng/l]/[10 ng/l])
HBWC = health-based water
concentration
HQ = hazard quotient
ng/l = nanograms per liter
PFAS
water
= the concentration of a specific PFAS in water
d)         USEPA,
under section 1412 of SDWA identifies in Table 1 to subsection (d) the BAT,
treatment technique, or other means available for achieving compliance with the
maximum contaminant levels for all regulated PFAS identified in subsection (c)
C = health-based water
concentration
HQ = hazard quotient
ng/l = nanograms per liter
PFAS
water
= the concentration of a specific PFAS in water
d)         USEPA,
under section 1412 of SDWA identifies in Table 1 to subsection (d) the BAT,
treatment technique, or other means available for achieving compliance with the
maximum contaminant levels for all regulated PFAS identified in subsection (c).
Table 1 to Subsection (d) BAT for
PFAS Listed in Subsection (c)(2)
CAS No.
Contaminant
BAT
Not Applicable
Hazard Index PFAS
GAC, HPAE, RO, NF
122499-17-6
HFPO-DA
GAC, HPAE, RO, NF
108427-53-8
PHFxS
GAC, HPAE, RO, NF
72007-68-2
PFNA
GAC, HPAE, RO, NF
45285-51-6
PFOA
GAC, HPAE, RO, NF
45298-90-6
PFOS
GAC, HPAE, RO, NF
Abbreviations (BAT)
GAC
Granular Activated Carbon
HPAE
Anion Exchange
NF
Nanofiltration
PTA
Packed Tower Aeration
RO
Reverse Osmosis
e)         USEPA,
under section 1412 of SDWA, identifies in Table 1 to subsection (e) the
affordable technology, treatment technique, or other means available to
suppliers serving 10,000 persons or fewer for achieving compliance with the
MCLs for all regulated PFAS identified in subsection (c)(2)
Section 611.311(e) List of SSCTs
for PFAS.
Small System Compliance Technologies
1
Affordable for Listed Small System Categories
2
Anion Exchange
All size categories.
GAC
All size categories.
Reverse Osmosis,
3
Nanofiltration
3
3,301-10,000.
1
Section
1412(b)(4)(E)(ii) of SDWA specifies that small system compliance technologies
(SSCTs) must be affordable and technically feasible for small systems.
2
SDWA specifies three
categories of small systems: (i) those serving 25 or more, but fewer than 501,
mall System Categories
2
Anion Exchange
All size categories.
GAC
All size categories.
Reverse Osmosis,
3
Nanofiltration
3
3,301-10,000.
1
Section
1412(b)(4)(E)(ii) of SDWA specifies that small system compliance technologies
(SSCTs) must be affordable and technically feasible for small systems.
2
SDWA specifies three
categories of small systems: (i) those serving 25 or more, but fewer than 501,
(ii) those serving more than 500, but fewer than 3,301, and (iii) those serving
more than 3,300, but fewer than 10,001.
3
Technology rejects a
large volume of water and may not be appropriate for areas where water quantity
may be an issue.
BOARD NOTE:
This Section derives
from 40 CFR 141.61.
More stringent state MCLs for 2,4-D, heptachlor, and heptachlor epoxide appear
at Section 611.310.  In 40 CFR 141.6(g), USEPA postponed the effectiveness of
the MCLs for aldicarb, aldicarb sulfone, and aldicarb sulfoxide until it took
further action on those MCLs. See 40 CFR 141.6(g) and 57 Fed. Reg. 22178 (May
27, 1992).  USEPA later stated that it anticipated taking no action until 2005
on a federal national primary drinking water regulation (NPDWR) applicable to
the aldicarbs. 68 Fed. Reg. 31108 (May 27, 2003).  In 2005, USEPA indicated no
projected date for final action on the aldicarbs.
See
70 Fed. Reg.
27501, 671 (May 16, 2005). An entry for the aldicarbs last appeared in USEPA's
Spring 2007 semiannual regulatory agenda, indicating no projected dates for
further action.
See
72 Fed. Reg. 23156, 97 (Apr. 30, 2007);
see also
72 Fed. Reg. 70118, 23 (Dec. 10, 2007) (the first USEPA regulatory agenda that
included no entry for the aldicarbs).  As of early 2022, USEPA did not include
the aldicarbs among the NPDWRs on its webpage.  USEPA, Ground Water and
Drinking Water, National Primary Drinking Water Regulations
(www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations;
accessed February 16, 2022)
70118, 23 (Dec. 10, 2007) (the first USEPA regulatory agenda that
included no entry for the aldicarbs).  As of early 2022, USEPA did not include
the aldicarbs among the NPDWRs on its webpage.  USEPA, Ground Water and
Drinking Water, National Primary Drinking Water Regulations
(www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations;
accessed February 16, 2022).  While the Board must maintain entries for
aldicarb, aldicarb sulfoxide, and aldicarb sulfone to maintain consistency with
the literal text of the federal rules (
see
Sections 7.2 and 17.5 of the
Act; 42 U.S.C. 300g-2; 40 CFR 142.10), the Board intends that no aldicarb
requirements apply in Illinois until after USEPA adopts such requirements, and
the Board removes this statement.

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