# Wis. Admin. Code NR § 106.07: Application of and compliance with water quality based effluent limitations in permits > Wisconsin · Regulations · In force URL: https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_07 ## Section - **Citation:** Wis. Admin. Code NR § 106.07 - **Heading:** Application of and compliance with water quality based effluent limitations in permits - **Jurisdiction:** Wisconsin - **Kind:** Regulations - **Status:** In force - **Text as of:** August 14, 2026 - **Source:** Compiled text - **Location:** Wisconsin Administrative Code / NR / Chapter NR 106 / § NR 106.07 ## Text Application of and compliance with water quality based effluent limitations in permits. (1) Permit monitoring frequency. The department shall determine on a case-by-case basis the monitoring frequency to be required for each water quality based effluent limitation in a permit. (2) General. Except as provided in subs. (3) and (4) , a chemical specific water quality-based effluent limitation that is calculated under this chapter shall be expressed in the permit as both a concentration limitation and a mass limitation unless the pollutant cannot appropriately be expressed by mass or a mass limitation is infeasible because the mass of the pollutant cannot be related to a measure of operation. Water quality-based mass limits for discharges of chlorine are not required in permits. The concentration limitation shall be expressed in units of mg/L or equivalent units. The mass limitation shall be expressed in units of kg/day or equivalent units. All of the following procedures shall be used when calculating mass limitations: (a) For dischargers subject to ch. NR 210 , an acute toxicity based concentration limitation that is derived by the procedure in s. NR 106.06 shall be converted to a mass limitation by using the discharger’s maximum effluent flow, expressed as a daily total flow, that is anticipated to occur for 24 continuous hours during the design life of the treatment facility. (b) For all other dischargers not subject to ch. NR 210 , an acute toxicity based concentration limitation that is derived by the procedures in s. NR 106.06 shall be converted to a mass limitation by using the discharger’s maximum effluent flow, expressed as a daily total flow, that has occurred for 24 continuous hours and represents normal operations. When calculating a mass limitation, the department may consider a projected increase in effluent flow that will occur when production is increased or modified, or another wastewater source, including storm water, that is added to an existing wastewater treatment facility imum effluent flow, expressed as a daily total flow, that has occurred for 24 continuous hours and represents normal operations. When calculating a mass limitation, the department may consider a projected increase in effluent flow that will occur when production is increased or modified, or another wastewater source, including storm water, that is added to an existing wastewater treatment facility. Limitations calculated under this paragraph are subject to the antidegradation requirements of ch. NR 207 . (c) A chronic toxicity, human health, or wildlife-based concentration limitation that is determined by the procedures in s. NR 106.06 shall be converted to a mass limitation by using the same effluent flow rate that was used in s. NR 106.06 (4) (d) to calculate the concentration limitation. (d) A chronic toxicity-based mass limitation that is determined by the procedures in s. NR 106.11 shall be converted to a concentration limitation by using an effluent flow rate from s. NR 106.06 (4) (d) . (3) Expression of concentration limitations in permits for continuous discharges subject to ch. NR 210. (a) Applicability. The procedures for expressing limitations in permits in this subsection apply to continuous discharges subject to ch. NR 210 when there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation based on fish and aquatic life protection, human health, or wildlife protection that is calculated under s. NR 106.06 . This subsection does not apply if another provision in this chapter or another Wisconsin administrative code chapter requires a different time period for expressing limits for a specific pollutant, type of discharge, or parameter, or if the department determines that expression of limitations in accordance with this subsection is impracticable under sub. (10) . t is calculated under s. NR 106.06 . This subsection does not apply if another provision in this chapter or another Wisconsin administrative code chapter requires a different time period for expressing limits for a specific pollutant, type of discharge, or parameter, or if the department determines that expression of limitations in accordance with this subsection is impracticable under sub. (10) . (b) Expression of water quality-based effluent limitations based on acute criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on an acute criterion or secondary value, that limitation shall be expressed as a daily maximum and included in the permit. (c) Expression of water quality-based effluent limitations based on chronic criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a chronic criterion or secondary value that limitation shall be expressed as a weekly average and included in the permit. (d) Expression of water quality-based effluent limitations based on human health or wildlife criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a human health or wildlife criterion or secondary value that limitation shall be expressed as a monthly average and included in the permit. sion of water quality-based effluent limitations based on human health or wildlife criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a human health or wildlife criterion or secondary value that limitation shall be expressed as a monthly average and included in the permit. (e) Additional permit limitations. Both a weekly average and monthly average permit limitation shall be included in a permit for a pollutant whenever any water quality-based effluent limitation for that pollutant is determined necessary under pars. (b) to (d) . A daily maximum limitation shall be included in a permit in addition to the weekly average and monthly average limitation if the daily maximum limitation is determined necessary under par. (b) . The department shall use all of the following procedures to include weekly average and monthly average limitations in permits: 1. If a daily maximum limitation is the only limitation determined necessary for a pollutant under s. NR 106.05 , a weekly average and monthly average limitation shall still be included in the permit and shall be set equal to the daily maximum limitation or the calculated weekly average and monthly average water quality-based effluent limitations, whichever is more restrictive. 2. If a weekly average limitation is determined necessary for a pollutant under s. NR 106.05 , but a monthly average limitation is not determined necessary for that pollutant in the permit under s. NR 106.05 , a monthly average limitation shall still be included in the permit and shall be set equal to the weekly average limitation or the monthly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. A daily maximum limitation shall be included if deemed necessary under s. NR 106.05 . 3. If a daily maximum and monthly average limitation are determined necessary in a permit for a pollutant under s uded in the permit and shall be set equal to the weekly average limitation or the monthly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. A daily maximum limitation shall be included if deemed necessary under s. NR 106.05 . 3. If a daily maximum and monthly average limitation are determined necessary in a permit for a pollutant under s. NR 106.05 , but a weekly average limit is not necessary for that pollutant under s. NR 106.05 , a weekly average limitation shall still be included in the permit for the pollutant and shall be set equal to the daily maximum limitation or the weekly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. 4. If a monthly average limitation is the only limitation determined to be necessary for a pollutant under s. NR 106.05 , a weekly average limitation shall still be included in the permit and shall be set equal to the weekly average water quality-based effluent limitation calculated under s. NR 106.06 , or a weekly average limitation calculated using the following procedure, whichever is more restrictive: 5. Limitations calculated under subds. 1. to 4. shall be expressed in terms of concentration unless the department determines that a mass limitation is also necessary to protect fish and aquatic life, human health, or wildlife due to the variability of effluent flow or stream flow or other site-specific factors. (4) Expression of concentration limitations in permits for continuous discharges not subject to ch. NR 210. ated under subds. 1. to 4. shall be expressed in terms of concentration unless the department determines that a mass limitation is also necessary to protect fish and aquatic life, human health, or wildlife due to the variability of effluent flow or stream flow or other site-specific factors. (4) Expression of concentration limitations in permits for continuous discharges not subject to ch. NR 210. (a) Applicability. The procedures for expressing limitations in this subsection apply to continuous discharges that are not subject to ch. NR 210 and when there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation based on fish and aquatic life protection, human health, or wildlife protection that is calculated under s. NR 106.06 . This subsection does not apply if another provision in this chapter or another Wisconsin administrate code chapter requires a different time period for expressing limits that is specific to a pollutant, type of discharge, or other parameter, or if the department determines that expression of limitations in accordance with this subsection is impracticable under sub. (10) . (b) Expression of water quality-based effluent limitations based on acute criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on an acute criterion or secondary value that limitation shall be expressed as a daily maximum and included in the permit. (c) Expression of water quality-based effluent limitations based on chronic criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a chronic criterion or secondary value that limitation shall be expressed as a weekly average and included in the permit. included in the permit. (c) Expression of water quality-based effluent limitations based on chronic criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a chronic criterion or secondary value that limitation shall be expressed as a weekly average and included in the permit. (d) Expression of water quality-based effluent limitations based on human health or wildlife criterion. If there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation calculated under s. NR 106.06 for a pollutant that is based on a human health or wildlife criterion or secondary value that limitation shall be expressed as a monthly average and included in the permit. (e) Additional permit limitations. Both a daily maximum and monthly average permit limitation shall be included in a permit for a pollutant whenever any water quality-based effluent limitation for that pollutant is determined necessary under pars. (b) to (d) . A weekly average limitation shall be included in a permit in addition to daily maximum and monthly average limitation if the weekly average limit is determined necessary under par. (c) . The department shall use all of the following procedures to include daily maximum and monthly average limitations in permits: 1. If a daily maximum limitation is the only limitation determined necessary for a pollutant under s. NR 106.05 , a monthly average limitation shall still be included in the permit and set equal to the daily maximum limitation or the monthly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. 2. If a weekly average limitation is the only limitation determined necessary for a pollutant under s n determined necessary for a pollutant under s. NR 106.05 , a monthly average limitation shall still be included in the permit and set equal to the daily maximum limitation or the monthly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. 2. If a weekly average limitation is the only limitation determined necessary for a pollutant under s. NR 106.05 a monthly average limitation shall still be included in the permit and shall be set equal to the weekly average limitation or the monthly average water quality-based effluent limitation calculated under s. NR 106.06 , whichever is more restrictive. A daily maximum limitation shall also be included in the permit and set equal to the daily maximum water quality-based effluent limitation calculated under s. NR 106.06 or a daily maximum limitation calculated using the following procedure, whichever is more restrictive: 3. If a monthly average limitation is determined necessary, but a daily maximum limitation is not determined necessary for that pollutant under s. NR 106.05 , a daily maximum limitation shall still be included in the permit and shall be set equal to the daily maximum water quality-based effluent limitation calculated under s. NR 106.06 or a daily maximum limitation calculated using the following procedure, whichever is more restrictive: 4. Limitations calculated under subds. 1. to 3. shall be expressed in terms of concentration unless the department determines that a mass limitation is also necessary to protect fish and aquatic life, human health, or wildlife due to the variability of effluent flow or stream flow or other site-specific factors. (5) Expression of concentration limitations in permits for noncontinuous discharges. : 4. Limitations calculated under subds. 1. to 3. shall be expressed in terms of concentration unless the department determines that a mass limitation is also necessary to protect fish and aquatic life, human health, or wildlife due to the variability of effluent flow or stream flow or other site-specific factors. (5) Expression of concentration limitations in permits for noncontinuous discharges. (a) Applicability. The procedures for expressing limitations in this subsection apply to seasonal discharges, discharges proportional to stream flow, or other unusual discharge situations that do not meet the definition of a continuous discharge under s. NR 205.03 (9g) when there is reasonable potential under s. NR 106.05 to exceed a water quality-based effluent limitation based on fish and aquatic life protection, human health, or wildlife protection. Water quality-based effluent limitations shall be calculated under s. NR 106.06 . (b) Acute reasonable potential. Pursuant to s. NR 106.05 , if there is reasonable potential to exceed a water quality-based effluent limitation for a pollutant that is based on an acute criterion or secondary value then the acute concentration limitation calculated under s. NR 106.06 shall be expressed as a daily maximum and included in the permit. (c) Chronic and human health or wildlife reasonable potential. Pursuant to s. NR 106.05 , if there is reasonable potential to exceed a water quality-based effluent limitation for a pollutant based on a chronic, a human health, or a wildlife criterion or secondary value, limitations shall be included in the permit and expressed on a case-by-case basis. The department shall consider all of the following factors: 1. Frequency and duration of discharge. 2. Total mass of discharge. 3. Maximum flow rate of discharge. 4. Whether the pollutant is subject to a technology-based limitation or other limitation expressed by mass, concentration, or other appropriate measure in the permit. (5m) Coefficient of variation. and expressed on a case-by-case basis. The department shall consider all of the following factors: 1. Frequency and duration of discharge. 2. Total mass of discharge. 3. Maximum flow rate of discharge. 4. Whether the pollutant is subject to a technology-based limitation or other limitation expressed by mass, concentration, or other appropriate measure in the permit. (5m) Coefficient of variation. (a) The coefficient of variation (CV) shall be calculated as the ratio of the standard deviation of the representative effluent data divided by the arithmetic average of the representative effluent data, except as provided in par. (b) . (b) If there are fewer than 10 representative data points the CV shall be set equal to 0.6. (c) When calculating the CV in par. (a) a monitoring result less than the limit of detection may be assigned a value of zero. If the effluent limitation is less than the limit of detection, the department may substitute a value other than zero for results less than the limit of detection, after considering the number of monitoring results that are greater than the limit of detection and if warranted when applying appropriate statistical techniques. (6) limitations below the level of detection or quantification. When the water quality based effluent limitation for any substance in a permit is less than the limit of detection or the limit of quantitation, the following conditions shall apply: (a) The permittee shall perform monitoring required in the permit using an acceptable analytical methodology for that substance in the effluent which produces the lowest limit of detection and limit of quantitation. (b) The permittee shall determine the limit of detection and limit of quantitation using a method specified by the department. it of quantitation, the following conditions shall apply: (a) The permittee shall perform monitoring required in the permit using an acceptable analytical methodology for that substance in the effluent which produces the lowest limit of detection and limit of quantitation. (b) The permittee shall determine the limit of detection and limit of quantitation using a method specified by the department. (c) Compliance with concentration and mass limitations shall be determined as follows: 1. When the water quality based effluent limitation is less than the limit of detection, effluent levels less than the limit of detection are in compliance with the effluent limitation. 2. When the water quality based effluent limitation is less than the limit of detection, effluent levels greater than the limit of detection, but less than the limit of quantitation are in compliance with the effluent limitation except when analytically confirmed and statistically confirmed by a sufficient number of analyses of multiple samples and use of appropriate statistical techniques. The department may require in a permit additional monitoring when effluent levels are between the limit of detection and the limit of quantitation. ## Nearby sections - [Wis. Admin. Code NR § 106.01 Purpose](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_01.md) - [Wis. Admin. Code NR § 106.02 Applicability](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_02.md) - [Wis. Admin. Code NR § 106.03 Definitions](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_03.md) - [Wis. Admin. Code NR § 106.04 General](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_04.md) - [Wis. Admin. Code NR § 106.05 Determination of the necessity for water quality based effluent limitations for toxic and organoleptic substances](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_05.md) - [Wis. Admin. Code NR § 106.06 Calculation of water quality based effluent limitations for toxic and organoleptic substances](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_06.md) - [Wis. Admin. Code NR § 106.07 Application of and compliance with water quality based effluent limitations in permits](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_07.md) - [Wis. Admin. Code NR § 106.08 Determination of the necessity for whole effluent toxicity testing requirements and limitations](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_08.md) - [Wis. Admin. Code NR § 106.09 Whole effluent toxicity data evaluation and limitations](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_09.md) - [Wis. Admin. Code NR § 106.10 Noncontact cooling water additives](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_10.md) - [Wis. Admin. Code NR § 106.11 Multiple discharges](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_11.md) - [Wis. Admin. Code NR § 106.14 Analytical methods and laboratory requirements](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_14.md) - [Wis. Admin. Code NR § 106.15 Limitations for mercury](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_15.md) - [Wis. Admin. Code NR § 106.30 Applicability](https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_30.md) --- Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/STATE_WI_ADC_NR_106_07. Check the current official text before relying on it. Not legal advice.