Klarifi Logo
Try for freeLog in
Klarifi Logo

Wastewater treatment plants in Wisconsin

391 facilities · 308 MGD combined flow

Klarifi tracks 391 publicly owned wastewater treatment plants in Wisconsin with a combined average flow of 308 MGD, serving about 2,897,609 residents. 50 plants treat more than 1 MGD and 4 more than 10 MGD; 147 use lagoon systems and 143 have digesters or biogas infrastructure. The largest is Milwaukee Metro Sew Dist Combi in Milwaukee at 95.1 MGD. 11 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 391 by average flow — browse the rest with the page links below.

390 plant locations in Wisconsin; dot size follows average flow.

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 →11 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 CombiMilwaukee95.1123WI0036820Mar 2024392
Green Bay Metropolitan Sewerage DistrictGreen Bay27.53—WIL065251Dec 20307
Racine Wastewater Treatment FacilityRacine14.4430WI0025194Sep 20196
La Crosse CityLa Crosse10.2920WI0029581Dec 20200
Janesville Wastewater UtilityJanesville9.9817.18WI0030350Jun 20250
Appleton City WWTFAppleton9.25—WI0023221Mar 20227
Fox River Water Pollution Control CenterBrookfield8.9510WI0023469Dec 202310
Oshkosh Wastewater Treatment FOshkosh8.4920WI0025038Dec 202334
Grand Chute-Menasha West SewerNeenah5.313.9WI0024686Jun 20223
Wausau Cty Wastewater Treatment PltWausau4.399.2WI0025739Dec 20230

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

Lagoon systems (147)Anaerobic digesters and biogas (143)Activated sludge and clarifiers (83)Oxidation ditches (62)

All 391 plants in Wisconsin

FacilityCityFlow (MGD)
Milwaukee Metro Sew Dist CombiMilwaukee95.1
Green Bay Metropolitan Sewerage DistrictGreen Bay27.53
Racine Wastewater Treatment FacilityRacine14.44
La Crosse CityLa Crosse10.29
Janesville Wastewater UtilityJanesville9.98
Appleton City WWTFAppleton9.25
Fox River Water Pollution Control CenterBrookfield8.95
Oshkosh Wastewater Treatment FOshkosh8.49
Grand Chute-Menasha West SewerNeenah5.31
Wausau Cty Wastewater Treatment PltWausau4.39
Beloit Wastewater Treatment FacilityBeloit3.79
Waukesha Waste Water Treatment PlantWaukesha3.15
Rib Mountain Sewage DistWausau2.94
Burlington Water Pollution ControlBurlington2.88
Watertown Wastewater TreatmentWatertown2.81
Stevens Point Wastewater Treatment FacilityStevens Point2.59
Sussex Wastewater Treatment FacilitySussex2.57
Marshfield Wastewater UtilityMarshfield2.42
Delafield Hartland Pollution CDelafield2.33
Wisconsin Rapids WWTFWisconsin Rapids2.32
Heart Of The Valley Metro Sewage DistrictKaukauna2.21
South Milwaukee Wastewater TreSouth Milwaukee2.18
Reedsburg Wastewater Treatment FacilityReedsburg2.02
Chippewa Falls WWTPChippewa Falls1.81
Menomonie Wastewater Treatment FacilityMenomonie1.72
Shawano Lake Sanitary District 1Shawano1.71
Whitewater City WWTFWhitewater1.61
Ripon Wastewater Treatment Plt (duplicate)Ripon1.59
Wpsc Marinette MgpMarinette1.55
River Falls WWTPRiver Falls1.53
Portage Wastewater Treatment FacilityPortage1.52
Sparta Wastewater Treatment FacilitySparta1.51
Monroe Wastewater Treatment FacilityMonroe1.5
Rice Lake Wastewater PltRice Lake1.45
Wi Dells Lake Delton Sew CommLake Delton1.4
Platteville Wastewater Treatment FacilityPlatteville1.34
Baraboo Water Resource Recovery FacilityBaraboo1.29
Antigo City OfAntigo1.21
Arcadia Wastewater Treatment FArcadia1.19
Salem Utility District No 2Trevor1.13
Waupaca Wastewater Treatment FacilityWaupaca1.11
Tomah Wastewater Treatment FacilityTomah1.11
Western Racine County Sewerage DistrictRochester1.08
New London Wastewater TreatmenNew London1.07
Stoughton Wastewater Treatment FacilityStoughton1.06
Sturgeon Bay UtilitiesSturgeon Bay1.06
Jefferson Wastewater TreatmentJefferson1.06
Kiel Wastewater Treatment FacilityKiel1.05
Port Washington WWTPPort Washington1.04
Columbus City WWTFColumbus1.03
Saukville Village Sewer UtilitySaukville0.98
Jackson Sewage Treatment PlantJackson0.95
Fontana-Walworth Water Pollution Control CommissionFontana0.9
Ashland Sewage UtilityAshland0.85
Slinger Wastewater Treatment FacilitySlinger0.77
New Richmond Wastewater TreatmNew Richmond0.73
Norway Tn Sanitary District 1 WWTFWind Lake0.73
Dodgeville Wastewater Treatment FacilityDodgeville0.72
Chilton Wastewater Treatment FChilton0.71
Green Lake Sanitary DistrictPrinceton0.69
Weyauwega Wastewater Treatment FacilityWeyauwega0.66
Whitehall Wastewater Treatment FacilityWhitehall0.65
Union Grove VillageUnion Grove0.6
Berlin City WWTFBerlin0.59
Beloit Town Wastewater Treatment FacilityBeloit0.55
Stanley Wastewater Treatment FacilityStanley0.53
Twin Lakes Wastewater Treatment FacTwin Lakes0.52
Turtle Lake Village OfTurtle Lake0.51
Consolidated Koshkonong Sanitary District SiteEdgerton0.49
Dousman Wastewater Treatment FacilityDousman0.48
Edgerton Wastewater Treatment FacilityEdgerton0.47
Brillion Wastewater TreatmentBrillion0.46
Denmark Wastewater Treatment FacilityDenmark0.46
Clintonville Wastewater Treatment PlantClintonville0.45
Black River Falls WWTFBlack River Falls0.42
Cross Plains WaterworksCross Plains0.4
Tomahawk WaterworksTomahawk0.39
West Salem Wastewater Treatment FacilityWest Salem0.39
Kewaskum Wastewater TreatmentKewaskum0.39
Horicon Wastewater Treatment FacilityHoricon0.39
Random Lake WaterworksRandom Lake0.38
Oconto Utility Commission WWTFOconto0.38
Marshall Wastewater Treatment FacilityMarshall0.37
Thorp Wastewater Treatment FacilityThorp0.36
Silver Lake Sanitary DistrictWautoma0.36
Cambridge/oakland Wastewater CommissionCambridge0.34
Black Creek Wastewater TreatmeBlack Creek0.34
Milton WaterworksMilton0.34
Algoma Wastewater Treatment FaAlgoma0.34
Dane Iowa Wastewater Commission WWTFMazomanie0.34
New Glarus Wastewater Treatment FacilityNew Glarus0.34
Rio Wastewater Treatment FacilityRio0.34
Durand WWTPDurand City0.33
Winneconne Wastewater Treatment PlantWinneconne0.32
Prescott Wastewater Treatment FacilityPrescott0.32
Ellsworth Wastewater TreatmentEllsworth0.32
Park Falls City OfPark Falls0.32
New Lisbon Wastewater Treatment FacilityNew Lisbon0.31
Paddock Lake Wastewater Trtmnt FacSalem0.31
Ladysmith City OfLadysmith0.3
Darlington Wastewater Treatment FacilityDarlington0.29
Amery City OfAmery0.28
Freedom Sanitary District #1Kaukauna0.28
Owen Wastewater Treatment FacilityOwen0.28
Lodi Wastewater Treatment FacilityLodi0.27
US Army Fort MccoyFort Mccoy0.27
Oostburg Wastewater Treatment PlantOostburg0.27
Holland Sd 1 Wastewater TrtmntHolland0.25
Osceola WWTFOsceola0.25
Hortonville Wastewater Treatment FacilityHortonville0.24
Mineral Point Wastewater Treatment FacilityMineral Point0.23
Port Edwards Wastewater Treatment FacilityPort Edwards0.23
Deerfield Wastewater Treatment FacilityDeerfield0.23
Bristol Utility District 1Bristol0.23
Howards Grove Wastewater Treatment FacilityHowards Grove0.23
Augusta Wastewater Treatment FacilityAugusta0.22
Somerset Wastewater Treatment FacilitySomerset0.22
Potosi-Tennyson Sewage Commission WWTFPotosi0.22
Marion Wastewater Treatment FaMarion0.21
Brodhead Wastewater Treatment FacilityBrodhead0.21
Monticello Wastewater Treatment FacilityMonticello0.21
Hilbert Wastewater Treatment FacilityHilbert0.2
Sister Bay Wastewater Treatment FacilitySister Bay0.2
Village Of Bloomfield WWTPGenoa City0.2
Fredonia Municipal Sewer And Water UtilityFredonia0.19
Belgium Wastewater Treatment FacilityBelgium0.19
St Croix Falls City OfSt Croix Falls0.19
Colfax Wastewater Treatment FacilityColfax0.19
Niagara Wastewater Treatment FacilityNiagara0.19
Adams Wastewater Treatment FacilityFriendship0.18
Nekoosa Wastewater Treatment FacilityNekoosa0.18
Spencer WaterworksSpencer0.18
Genoa City Village WWTFGenoa City0.17
Grantsburg Village OfGrantsburg0.17
Belleville Wastewater Treatment FacilityBelleville0.17
Clinton Wastewater Treatment FacilityClinton0.17
Campbellsport Wastewater TrtmnCampbellsport0.17
Wittenberg Wastewater Treatment FacilityWittenberg0.17
Washburn WWTPWashburn0.17
Shullsburg Wastewater Treatment FacilityShullsburg0.16
Reeseville Wastewater Treatment FacilityReeseville0.16
Iron Ridge VillageIron Ridge0.15
Green Lake Wastewater Treatment FacilityGreen Lake0.15
Westfield WWTFWestfield0.15
Palmyra Wastewater Treatment FacilityPalmyra0.15
City Of MontrealMontreal0.14
Hustisford WWTPHustisford0.14
Colby Wastewater Treatment FacColby0.14
Cuba City Wastewater Treatment FacilityCuba City0.14
Spring Green Wastewater Treatment FacilitySpring Green0.14
Hillsboro Wastewater Treatment FacilityHillsboro0.14
Redgranite Wastewater Treatment FacilityRedgranite0.14
Wazee Area Wastewater CommissionBlack River Falls0.13
Galesville Wastewater Treatment PlantGalesville0.13
Oneida WWTFOneida0.13
Trempealeau Wastewater Treatment FacilityTrempealeau0.13
Boyceville WaterworksBoyceville0.12
Sharon Wastewater Treatment FacilitySharon0.12
Cleveland Wastewater Treatment FacilityCleveland0.12
Keshena WWTFKeshena0.12
Cedar Grove Wastewater Trtmnt FacilCedar Grove0.12
Coon Valley Wastewater Treatment FacilityCoon Valley0.12
Theresa Wastewater Treatment FacilityTheresa0.12
Greater Bayfield WWTP CommissionBayfield0.12
Eleva Strum Joint Sewerage Commission WWTFStrum0.11
Princeton WWTFPrinceton0.11
Roberts Wastewater Treatment FacilityRoberts0.11
Fish Creek Sd1 Wastewater Treatment FacilityFish Creek0.11
Manawa Wastewater Treatment FacilityManawa0.11
Coleman Wastewater Treatment FacilityColeman0.11
Fountain City WWTFFountain City0.11
Eden Wastewater Treatment FaciEden0.11
Iola Wastewater Treatment FacilityIola0.11
Footville Wastewater Treatment FacilityFootville0.11
Athens Wastewater Treatment FaAthens0.1
Stratford Wastewater Treatment FacilityStratford0.1
Oakfield Wastewater Treatment FacilityOakfield0.1
Kieler Sanitary District 1Kieler0.1
Yorkville Sewer Utility District No 1Sturtevant0.1
Red Cliff Band WWTFBayfield0.1
Mellen City OfMellen0.1
Little Suamico Sanitary District No 1Little Suamico0.09
Independence Wastewater Treatment PlantIndependence0.09
Cascade Wastewater Treatment FacilityCascade0.09
Fremont Orihula Wolf River Joint S CFremont0.09
Vesper Wastewater Treatment FacilityVesper0.09
Ashippun Sanitary DistrictAshippun0.09
Clayton Village OfClayton0.09
Wrightstown Sanitary District No 1 WWTFGreenleaf0.09
Crivitz Wastewater Treatment FacilityCrivitz0.09
Embarrass Wastewater TreatmentEvansville0.09
Siren Wastewater Treatment FacSiren0.09
Belmont Wastewater Treatment FacilityBelmont0.09
Edgar Wastewater Treatment FacilityEdgar0.09
Ephraim Wastewater Treatment FacilityEphraim0.08
Cashton Wastewater Treatment FacilityCashton0.08
Pittsville Water And Sewer Dept WWTFPittsville0.08
Spring Valley Wastewater Treatment FacilitySpring Valley0.08
Onion River Wastewater CommissionHingham0.08
NeopitKeshena0.08

Page

1
2

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 September 22, 2026.

Try Klarifi for free

Create your own trial account and explore how Klarifi can help you.

Try for free