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Wastewater treatment plants in Wisconsin

394 facilities · 426 MGD combined flow

Klarifi tracks 394 publicly owned wastewater treatment plants in Wisconsin with a combined average flow of 426 MGD, serving about 3,285,764 residents. 59 plants treat more than 1 MGD and 9 more than 10 MGD; 140 use lagoon systems and 146 have digesters or biogas infrastructure. The largest is Milwaukee Metro Sew Dist Combi in Milwaukee at 103.5 MGD. 12 NPDES permits expire this year and 1 next year.

Every plant below links to a profile with average and design flow, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city. Treatment technology and verified contacts are shown with a free Klarifi account. Showing facilities 1–200 of 394 by average flow — browse the rest with the page links below.

393 plant locations in Wisconsin; dot size follows average flow. Boundaries: U.S. Census Bureau.

NPDES permits and renewals in Wisconsin

Every plant discharges under an NPDES permit that is renewed every five years, usually with tighter limits. The renewal year is the year a plant budgets for upgrades.

All NPDES permits in Wisconsin →12 permits expiring in 2026 →Find plants near you on the map →

Largest wastewater treatment plants in Wisconsin

The 10 largest publicly owned wastewater treatment plants in Wisconsin by average flow, with NPDES permit, expiry and three-year violation count. Source: EPA ICIS-NPDES via Klarifi.
FacilityCityAvg flow (MGD)Design (MGD)NPDES permitExpiresViolations (3y)
Milwaukee Metro Sew Dist CombiMilwaukee103.5123WI0036820Mar 2024392
EPA Superfund Site: Madison Metropolitan Sewerage District LagoonsMadison39.37—WIG009756Sep 20262
Green Bay Metropolitan Sewerage DistrictGreen Bay36.81—WIL065251Dec 20307
Racine Wastewater Treatment FacilityRacine20.8930WI0025194Sep 20196
Neenah-Menasha Sewerage Commission WWTFMenasha12.3318WI0026085Jun 2022194
Janesville Wastewater UtilityJanesville11.0317.18WI0030350Jun 20250
Oshkosh Wastewater Treatment FOshkosh10.5620WI0025038Dec 202333
La Crosse CityLa Crosse10.2120WI0029581Dec 20200
Fox River Water Pollution Control CenterBrookfield10.1110WI0023469Dec 20239
Appleton City WWTFAppleton9.3—WI0023221Mar 20227

Treatment technology for each plant is shown with a free Klarifi account. Create one →

The 50 largest plants in Wisconsin →EPA enforcement actions in Wisconsin →Wisconsin capital improvement plans →

Wisconsin plants by treatment technology

Anaerobic digesters and biogas (146)Lagoon systems (140)Activated sludge and clarifiers (85)Oxidation ditches (63)

All 394 plants in Wisconsin

FacilityCityFlow (MGD)
Milwaukee Metro Sew Dist CombiMilwaukee103.5
EPA Superfund Site: Madison Metropolitan Sewerage District LagoonsMadison39.37
Green Bay Metropolitan Sewerage DistrictGreen Bay36.81
Racine Wastewater Treatment FacilityRacine20.89
Neenah-Menasha Sewerage Commission WWTFMenasha12.33
Janesville Wastewater UtilityJanesville11.03
Oshkosh Wastewater Treatment FOshkosh10.56
La Crosse CityLa Crosse10.21
Fox River Water Pollution Control CenterBrookfield10.11
Appleton City WWTFAppleton9.3
Grand Chute-Menasha West SewerNeenah6.52
Hartford Water Pollution Control FacilityHartford5.48
Wausau Cty Wastewater Treatment PltWausau5.3
Heart Of The Valley Metro Sewage DistrictKaukauna4.54
Beloit Wastewater Treatment FacilityBeloit4.15
Watertown Wastewater TreatmentWatertown3.51
Rib Mountain Sewage DistWausau3.48
City Of Sun Prairie SiteSun Prairie3.41
Waukesha Waste Water Treatment PlantWaukesha3.33
Burlington Water Pollution ControlBurlington3.21
Marshfield Wastewater UtilityMarshfield2.9
Wisconsin Rapids WWTFWisconsin Rapids2.88
South Milwaukee Wastewater TreSouth Milwaukee2.85
Stevens Point Wastewater Treatment FacilityStevens Point2.77
Sussex Wastewater Treatment FacilitySussex2.75
Fort Atkinson Wastewater TreatFort Atkinson2.45
Cedarburg Water Recycling CenterCedarburg2.33
Delafield Hartland Pollution CDelafield2.24
Shawano Lake Sanitary District 1Shawano2.22
Reedsburg Wastewater Treatment FacilityReedsburg1.93
City Of PlymouthPlymouth1.93
Wpsc Marinette MgpMarinette1.89
Chippewa Falls WWTPChippewa Falls1.81
Salem Utility District No 2Trevor1.71
Sturgeon Bay UtilitiesSturgeon Bay1.7
Monroe Wastewater Treatment FacilityMonroe1.64
Menomonie Wastewater Treatment FacilityMenomonie1.6
Whitewater City WWTFWhitewater1.57
Portage Wastewater Treatment FacilityPortage1.55
Port Washington WWTPPort Washington1.5
Ripon Wastewater Treatment Plt (duplicate)Ripon1.48
River Falls WWTPRiver Falls1.4
Wi Dells Lake Delton Sew CommLake Delton1.38
Antigo City OfAntigo1.34
Sparta Wastewater Treatment FacilitySparta1.33
Waupun City WWTFWaupun1.32
New London Wastewater TreatmenNew London1.31
Baraboo Water Resource Recovery FacilityBaraboo1.31
Rice Lake Wastewater PltRice Lake1.28
Arcadia Wastewater Treatment FArcadia1.25
Platteville Wastewater Treatment FacilityPlatteville1.23
Jackson Sewage Treatment PlantJackson1.22
Western Racine County Sewerage DistrictRochester1.19
Kiel Wastewater Treatment FacilityKiel1.18
Jefferson Wastewater TreatmentJefferson1.17
Tomah Wastewater Treatment FacilityTomah1.14
Columbus City WWTFColumbus1.11
Stoughton Wastewater Treatment FacilityStoughton1.1
Fontana-Walworth Water Pollution Control CommissionFontana1.06
Norway Tn Sanitary District 1 WWTFWind Lake0.99
Saukville Village Sewer UtilitySaukville0.99
Waupaca Wastewater Treatment FacilityWaupaca0.96
Ashland Sewage UtilityAshland0.95
Rhinelander Water & Wastewater-Bg544Rhinelander0.94
Potosi-Tennyson Sewage Commission WWTFPotosi0.92
Chilton Wastewater Treatment FChilton0.9
Berlin City WWTFBerlin0.9
Union Grove VillageUnion Grove0.88
Slinger Wastewater Treatment FacilitySlinger0.76
New Richmond Wastewater TreatmNew Richmond0.71
Weyauwega Wastewater Treatment FacilityWeyauwega0.7
Brillion Wastewater TreatmentBrillion0.66
Green Lake Sanitary DistrictPrinceton0.65
Clintonville Wastewater Treatment PlantClintonville0.64
Lake Mills Wastewater Treatment FacilityLake Mills0.61
Juneau UtilitiesJuneau0.6
Stanley Wastewater Treatment FacilityStanley0.59
Mauston Wastewater Treatment FacilityMauston0.58
Twin Lakes Wastewater Treatment FacTwin Lakes0.58
Beloit Town Wastewater Treatment FacilityBeloit0.58
Denmark Wastewater Treatment FacilityDenmark0.57
Turtle Lake Village OfTurtle Lake0.55
West Salem Wastewater Treatment FacilityWest Salem0.54
Edgerton Wastewater Treatment FacilityEdgerton0.53
Whitehall Wastewater Treatment FacilityWhitehall0.52
Oconto Utility Commission WWTFOconto0.51
Red Cliff Band WWTFBayfield0.49
Algoma Wastewater Treatment FaAlgoma0.49
Kewaskum Wastewater TreatmentKewaskum0.48
Horicon Wastewater Treatment FacilityHoricon0.45
Dodgeville Wastewater Treatment FacilityDodgeville0.44
Paddock Lake Wastewater Trtmnt FacSalem0.44
Winneconne Wastewater Treatment PlantWinneconne0.43
Tomahawk WaterworksTomahawk0.41
Black River Falls WWTFBlack River Falls0.41
Black Creek Wastewater TreatmeBlack Creek0.4
Random Lake WaterworksRandom Lake0.4
Cambridge/oakland Wastewater CommissionCambridge0.37
Thorp Wastewater Treatment FacilityThorp0.36
Port Edwards Wastewater Treatment FacilityPort Edwards0.35
Marshall Wastewater Treatment FacilityMarshall0.35
Cross Plains WaterworksCross Plains0.35
Silver Lake Sanitary DistrictWautoma0.34
Freedom Sanitary District #1Kaukauna0.34
Dane Iowa Wastewater Commission WWTFMazomanie0.34
Oostburg Wastewater Treatment PlantOostburg0.34
New Glarus Wastewater Treatment FacilityNew Glarus0.34
Bristol Utility District 1Bristol0.34
Milton WaterworksMilton0.33
Lodi Wastewater Treatment FacilityLodi0.33
Durand WWTPDurand City0.33
Wi Dnr - Richard Bong State Recreation AreaKansasville0.31
Owen Wastewater Treatment FacilityOwen0.31
Nekoosa Wastewater Treatment FacilityNekoosa0.31
Hortonville Wastewater Treatment FacilityHortonville0.31
Park Falls City OfPark Falls0.3
Ladysmith City OfLadysmith0.3
New Lisbon Wastewater Treatment FacilityNew Lisbon0.29
Wrightstown Sewer & Water UtilityWrightstown0.29
Bloomer Wastewater Treatment PlantBloomer0.29
Neillsville Wastewater Treatment FacilityNeillsville0.29
Hatfield Sanitary DistrictMerrillan,0.29
Auburndale Wastewater Treatment FacilityAuburndale0.28
Marion Wastewater Treatment FaMarion0.28
Village Of Bloomfield WWTPGenoa City0.27
Amery City OfAmery0.27
Darlington Wastewater Treatment FacilityDarlington0.27
Clinton Wastewater Treatment FacilityClinton0.26
Prescott Wastewater Treatment FacilityPrescott0.26
US Army Fort MccoyFort Mccoy0.26
Belgium Wastewater Treatment FacilityBelgium0.26
Mineral Point Wastewater Treatment FacilityMineral Point0.25
Holland Sd 1 Wastewater TrtmntHolland0.25
Gillett Wastewater Treatment FacilityGillett0.24
Fredonia Municipal Sewer And Water UtilityFredonia0.24
Hilbert Wastewater Treatment FacilityHilbert0.24
Spencer WaterworksSpencer0.23
Monticello Wastewater Treatment FacilityMonticello0.23
Wittenberg Wastewater Treatment FacilityWittenberg0.23
Brodhead Wastewater Treatment FacilityBrodhead0.22
Edgar Wastewater Treatment FacilityEdgar0.22
Genoa City Village WWTFGenoa City0.21
Prentice Village OfPrentice0.21
Augusta Wastewater Treatment FacilityAugusta0.21
St Croix Falls City OfSt Croix Falls0.21
Niagara Wastewater Treatment FacilityNiagara0.21
Deerfield Wastewater Treatment FacilityDeerfield0.2
Dousman Wastewater Treatment FacilityDousman0.2
Somerset Wastewater Treatment FacilitySomerset0.2
City Of MontrealMontreal0.19
Princeton WWTFPrinceton0.19
Campbellsport Wastewater TrtmnCampbellsport0.19
Colby Wastewater Treatment FacColby0.19
Reeseville Wastewater Treatment FacilityReeseville0.19
Green Lake Wastewater Treatment FacilityGreen Lake0.18
Belleville Wastewater Treatment FacilityBelleville0.18
Clayton Village OfClayton0.18
Oakfield Wastewater Treatment FacilityOakfield0.18
Washburn WWTPWashburn0.18
Oneida WWTFOneida0.17
Hillsboro Wastewater Treatment FacilityHillsboro0.17
Adams Wastewater Treatment FacilityFriendship0.17
Theresa Wastewater Treatment FacilityTheresa0.17
Cedar Grove Wastewater Trtmnt FacilCedar Grove0.17
Hustisford WWTPHustisford0.17
Shullsburg Wastewater Treatment FacilityShullsburg0.17
Sister Bay Wastewater Treatment FacilitySister Bay0.16
Coleman Wastewater Treatment FacilityColeman0.16
Lakeland Sanitary District # 1Minocqua0.16
NeopitKeshena0.16
Palmyra Wastewater Treatment FacilityPalmyra0.16
Westfield WWTFWestfield0.16
Cleveland Wastewater Treatment FacilityCleveland0.16
Embarrass Wastewater TreatmentEvansville0.15
Glidden Sanitary DistrictGlidden0.15
Glenwood City Wastewater Treatment FacilityGlenwood City0.15
Redgranite Wastewater Treatment FacilityRedgranite0.15
Ashippun Sanitary DistrictAshippun0.15
Boyceville WaterworksBoyceville0.15
Keshena WWTFKeshena0.14
Athens Wastewater Treatment FaAthens0.14
Mellen City OfMellen0.14
Wazee Area Wastewater CommissionBlack River Falls0.14
Stratford Wastewater Treatment FacilityStratford0.14
Eden Wastewater Treatment FaciEden0.14
Trempealeau Wastewater Treatment FacilityTrempealeau0.14
Spring Green Wastewater Treatment FacilitySpring Green0.14
Little Suamico Sanitary District No 1Little Suamico0.13
Larsen Winchester Sd WW TrtmntWinchester0.13
Cuba City Wastewater Treatment FacilityCuba City0.13
Galesville Wastewater Treatment PlantGalesville0.13
Iron Ridge VillageIron Ridge0.12
Manawa Wastewater Treatment FacilityManawa0.12
Eleva Strum Joint Sewerage Commission WWTFStrum0.12
Roberts Wastewater Treatment FacilityRoberts0.12
Fremont Orihula Wolf River Joint S CFremont0.11
Vesper Wastewater Treatment FacilityVesper0.11
Crivitz Wastewater Treatment FacilityCrivitz0.11
Greater Bayfield WWTP CommissionBayfield0.11
Yorkville Sewer Utility District No 1Sturtevant0.11

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Wastewater treatment in Wisconsin: questions

Sources and methodology

Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.

Data refreshed October 26, 2026.

Wastewater terms: WWTP · POTW · MGD · NPDES permit · Ozonation · Activated sludge · all terms

Cite this page

Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.

Klarifi. “Wastewater treatment plants in Wisconsin.” Updated October 26, 2026. https://klarifi.io/facilities/wisconsin

Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.

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