A water quality variance is a temporary change in a state's water quality standard for a specific pollutant and its relevant criteria, allowing deviation from meeting a water quality-based effluent limit for a particular discharger. Federal and state regulations afford the flexibility to adopt a variance in some situations. For example, a discharger may be uncertain if it can ultimately meet permit limits and either wants to more fully assess its ability before investing in expensive controls, or the discharger anticipates less-expensive control technology becoming available in the near term. In these and other situations, variances are appropriate if they meet the criteria and provisions set by U.S. Environmental Protection Agency (EPA) and MPCA.
The EPA allows states to adopt variance provisions, but has ultimate approval over variances proposed by MPCA. As the agency delegated to implement the Clean Water Act, MPCA may grant variances through the National Pollution Discharge Elimination System/State Disposal System permit program. Because of this collaboration, MPCA must assess a variance using the same conditions and criteria that EPA uses. This will ensure a smooth processing of variance requests.
Guidance documents
Resources to help determine if a water quality variance is an allowable option for your permitted facility.
Chloride
Visit the Water permit holders and chloride page for information on chloride standard variances for wastewater treatment facilities.
Sulfate
- Visit the Protecting wild rice waters page for more information on the implementation of the wild rice sulfate standard.
- Learn more about the sulfate multi-discharger variance that the MPCA is considering.
Proposed variances
City of Avon Wastewater Treatment Plant
Reevaluation of Highest Attainable Condition
- Permit ID: MN0047325
- Pollutant (or restriction) for which variance is granted: Chloride
- Rule citation: 7050.0222, subp. 4, Total Chloride
- Receiving water: Spunk Creek (Mississippi River - Sartell Watershed)
- Date approved: Feb. 25, 2020; permit issued March 15, 2020 (limits and monitoring effective April 1, 2020)
- Variance term: 15 years (10 remaining at time of reevaluation)
Federal and state rules require variances with a term greater than five years to have their Highest Attainable Condition reevaluated at least every five years. MPCA reevaluated both the eligibility conditions and Highest Attainable Condition for Avon WWTP and has made a preliminary determination the facility is eligible to retain the variance for the next five years with the updated conditions and HAC.
To review and comment on the full Highest Attainable Condition Reevaluation and draft permit, visit the Public comments web page for the City of Avon WWTP permit re-issuance.
City of Holdingford
- Permit ID: MN0023710
- Pollutant (or restriction) for which variance is proposed: Chloride
- Rule citation: 7050.0222, subp. 4, Total Chloride
- Proposed variance term: 15 years
- Receiving water: South Two River in the Upper Mississippi River Basin
- Public comment period: April 18 through June 17, 2025
To review and comment on the proposed permit and variance, visit the Public comments web page.
Facilities requesting chloride variances must demonstrate that they are achieving the “highest attainable condition,” which prevents worsening pollution while a path to chloride reduction is identified and followed. The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.
Public meetings are required for water quality standard variances. An online public meeting is planned for June 3, 2025, for the City of Holdingford variance request.
Active variances
Details on variances in National Pollutant Discharge Elimination System/State Disposal System permits issued by the MPCA. This list is updated to meet reporting requirements under Minn. R. 7050.0190, subps. 2 and 9, and 7052.0280 subp. 7.
- Chisago Lakes Joint Sewage Treatment Commission Facility
Permit ID: MN0055808
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed Ditch in the Lower St. Croix River Watershed
Date approved: March 5, 2025; permit reissued April 1, 2025
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Mayer Wastewater Treatment Facility
Permit ID: MN0021202
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: South Fork of Crow River (South Fork Crow River Watershed)
Date approved: Feb. 26, 2025; permit reissued March 17, 2025
Variance term: 10 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- City of Pelican Rapids Wastewater Treatment Facility
Permit ID: MN0022225
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Pelican River in the Otter Tail River Watershed
Date approved: Nov. 8, 2024; permit reissued Dec. 2, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Grand Marais Wastewater Treatment Facility
Permit ID: MN0020010
Pollutant (or restriction) for which variance is proposed: Mercury
Rule citation: 7052.0100, subp. 2, Total Mercury
Receiving water: Lake Superior
Date approved: Oct. 31, 2024; permit reissued Nov. 15, 2024
Variance term: 5 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific mercury action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created mercury pollutant minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Kerkhoven Wastewater Treatment Facility
Permit ID: MN0020583
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: County Ditch 61 in the Chippewa River Watershed
Date approved: Sept. 4, 2024; permit reissued Oct. 1, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Tri-City Wastewater Systems Board Treatment Facility
Permit ID: MN0025224
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: County Ditch 87 in the Le Sueur River Watershed
Date approved: Aug. 19, 2024; permit reissued Sept. 1, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Nerstrand Wastewater Treatment Facility
Permit ID: MN0065668
Pollutant (or restriction) for which variance is proposed: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed ditch in the Cannon River Watershed
Date approved: July 26, 2024; permit reissued Aug. 19, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Lonsdale Wastewater Treatment Facility
Permit ID: MN0031241
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed ditch in the Cannon River Watershed
Date approved: July 17, 2024; permit reissued Aug. 15, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- New Richland Wastewater Treatment Facility
Permit ID: MN0021032
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed ditch in the Le Sueur River Watershed
Date approved: July 19, 2024; permit reissued Aug. 7, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Dawson Wastewater Treatment Facility
Permit ID: MN0021881
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: County Judicial Ditch 4 (Lac qui Parle River Watershed)
Date approved: April 8, 2024; permit reissued May 1, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Altura Wastewater Treatment Facility
Permit ID: MN0021831
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed dry run in the Mississippi River – Winona Watershed
Date approved: April 3, 2024; permit reissued April 12, 2024
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Marshall Wastewater Treatment Facility
Permit ID: MN0022179
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Redwood River (Redwood River Watershed)
Date approved: Feb. 1, 2024; permit reissued March 1, 2024
Variance term: 10 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- City of Saint James Wastewater Treatment Plant
Permit ID: MN0024759
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Saint James Creek (Watonwan River Watershed)
Date approved: Oct. 24, 2023; permit reissued Nov. 1, 2023
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance. This variance was approved for a 15-year term, with re-evaluations every five years.- Lewiston Wastewater Treatment Plant
Permit ID: MN0023965
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: This facility discharges to a dry run, the headwater of Rush Creek (Root River Watershed)
Date approved: July 24, 2023; permit reissued Aug. 4, 2023
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Lester Prairie Wastewater Treatment Plant
Permit ID: MN0023957
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: South Fork Crow River (South Fork Crow River Watershed)
Date approved: June 23, 2023; permit reissued June 30, 2023
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- Western Lake Superior Sanitary District (WLSSD)
Permit ID: MN0049786
Pollutant (or restriction) for which variance is granted: fecal coliform (year-round disinfection) and mercury
Rule citation: 7053.0215 subp. 1 and 7052.0100 subp. 5, respectively (related to pollutants above)
Receiving water: St. Louis Bay (St. Louis River) and Superior Bay to Lake Superior
Date approved: May 19, 2023 (mercury variance)
Permit reissuance: May 23, 2023 (includes variances for fecal coliform and year-round disinfection)
Variance term: 5 years
Restrictions in lieu of pollutant limit/restriction: Interim mercury effluent limits lower than the previous NPDES/SDS permit; additional mercury monitoring; further investigation of potential mercury removal technologies. Compliance with a fecal coliform limit from April 1 through Oct. 31 of each year; monitoring the SD001 station year-round and requires intervention disinfection limits if monitoring at two drinking water intakes exceed a specified numeric level; evaluate alternative disinfection options.- Waseca Wastewater Treatment Plant
Permit ID: MN0020796
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Unnamed creek (Le Sueur River Watershed)
Date approved: March 30, 2023; permit reissued April 3, 2023
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: The MPCA has determined the highest attainable condition of the receiving water is most appropriately achieved through combining (1) a facility-specific interim effluent limit, (2) a facility-specific chloride action tree, to be submitted with the variance application, which identifies actions to be taken immediately upon permit issuance, and (3) a permittee-created chloride Investigation and minimization plan, per 40 CFR 131.14(b)(1)(iii). The plan is due within 180 days of permit reissuance.- City of Albert Lea Wastewater Treatment Plant
Permit ID: MN0041092
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Shell Rock River (Shell Rock River Watershed)
Date approved: Dec. 17, 2021; permit issued Feb. 1, 2022
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: Chloride Investigation & Minimization Plan due 180 days after issuance that includes iterative process to identify sources and incorporate source reduction measures. Alternate limits apply throughout the variance term (15 years) to be updated every 5 years based on re-evaluation (40 CFR 131.14(b)(1)(iii)).- Glacial Lakes Sanitary Sewer and Water District
Permit ID: MN0052752
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Middle Fork of the Crow River (North Fork Crow River Watershed)
Variance term: 15 years
Date approved: Dec. 14, 2021; permit issued Jan. 4, 2022
Restrictions in lieu of pollutant limit/restriction: Chloride Investigation & Minimization Plan due 180 days after issuance that includes iterative process to identify sources and incorporate source reduction measures. Alternate limits apply throughout the variance term (15 years) to be updated every 5 years based on re-evaluation (40 CFR 131.14(b)(1)(iii)).- City of Worthington Wastewater Treatment Plant
Permit ID: MN0031186
Pollutant (or restriction) for which variance is granted: Total Chloride
Rule citation: 7050.0222, subp. 2
Receiving water: Okabena Creek (Des Moines River – Headwaters Watershed)
Date approved: May 4, 2021; permit issued May 7, 2021
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: Plan due 180 days after issuance that includes iterative process to reduce sources identified in the variance request form, identify other sources, and incorporate source reduction measures. Alternate limits apply throughout the variance term (15 years) to be updated every 5 years based on re-evaluation (40 CFR 131.14(b)(1)(iii)).- Southern Minnesota Beet Sugar – Renville
Permit ID: MN0040665
Pollutant (or restriction) for which variance is granted: bicarbonates, hardness, total dissolved solids, total salinity, and specific conductance
Rule citation: 7050.0223, 7050.0224, 7050.0210
Receiving water: County Ditch 45
Date approved: Dec. 16, 2020; permit issued Dec. 18, 2020
Variance term: 5 years
Restrictions in lieu of pollutant limit/restriction: Alternate effluent limitation for specific conductance and continued reductions in the discharge through implementation of a dissolved mineral reduction program.- Alexandria Lake Area Sanitary District (ALASD)
Permit ID: MN0040738
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Lake Winona (Mississippi River – Winona Watershed)
Date approved: Oct. 28, 2020; permit issued Nov. 15, 2020
Variance term: 8 years
Restrictions in lieu of pollutant limit/restriction: Chloride Investigation & Minimization Plan due 180 days after issuance that includes iterative process to identify sources and incorporate source reduction measures. Alternate limits apply throughout the variance term (8 years) to be updated every 5 years based on re-evaluation (40 CFR 131.14(b)(1)(iii)).- Avon Wastewater Treatment Plant
Permit ID: MN0047325
Pollutant (or restriction) for which variance is granted: Chloride
Rule citation: 7050.0222, subp. 4, Total Chloride
Receiving water: Spunk Creek (Mississippi River – Sartell Watershed)
Date approved: Feb. 25, 2020; permit issued March 15, 2020 (limits and monitoring effective April 1, 2020)
Variance term: 15 years
Restrictions in lieu of pollutant limit/restriction: Chloride Investigation & Minimization Plan due 180 days after issuance that includes iterative process to identify sources and incorporate source reduction measures. Alternate limits apply throughout the variance term (15 years) to be updated every 5 years based on re-evaluation (40 CFR 131.14(b)(1)(iii)).