Klarifi Logo
Try for freeLog in
Klarifi Logo

Wastewater treatment plants in Ohio

843 facilities · 1,320 MGD combined flow

Klarifi tracks 843 publicly owned wastewater treatment plants in Ohio with a combined average flow of 1,320 MGD, serving about 7,312,390 residents. 182 plants treat more than 1 MGD and 25 more than 10 MGD; 196 use lagoon systems and 111 have digesters or biogas infrastructure. The largest is Southerly Wastewater Treatment Plant in Lockbourne at 112.28 MGD. 108 NPDES permits expire this year and 189 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 843 by average flow — browse the rest with the page links below.

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

NPDES permits and renewals in Ohio

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 Ohio →108 permits expiring in 2026 →189 permits expiring in 2027 →170 permits expiring in 2028 →Find plants near you on the map →

Largest wastewater treatment plants in Ohio

The 10 largest publicly owned wastewater treatment plants in Ohio 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)
Southerly Wastewater Treatment PlantLockbourne112.28—OHL024741Dec 20309
Southerly Wastewater Treatment CenterCleveland110.09—OHL024651Dec 20304
Akron WRFAkron59.6290OH0023833Aug 20280
City Of Dayton Water Reclamation Facility (0857100983)Dayton51.6972OH0024881Apr 202717
Metropolitan Sewer Dis Little Miami WWTPCincinnati44.3255OH0025453Jun 20308
Waste Water Treatment PlantYoungstown33.235OH0028223Oct 2028231
Neorsd Westerly Wwt ComplexCleveland27.5435OH0024660Jun 20300
City Of CantonCanton25.439OH0024350May 20281
Middletown Wastewater Treatment PlantMiddletown21.1926OH0026522Dec 202685
City Of Euclid, Wastewater Treatment PlantEuclid18.1122OH0031062Aug 202912

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

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

Ohio plants by treatment technology

Activated sludge and clarifiers (300)Lagoon systems (196)Anaerobic digesters and biogas (112)Oxidation ditches (112)

All 843 plants in Ohio

FacilityCityFlow (MGD)
Southerly Wastewater Treatment PlantLockbourne112.28
Southerly Wastewater Treatment CenterCleveland110.09
Akron WRFAkron59.62
City Of Dayton Water Reclamation Facility (0857100983)Dayton51.69
Metropolitan Sewer Dis Little Miami WWTPCincinnati44.32
Waste Water Treatment PlantYoungstown33.2
Neorsd Westerly Wwt ComplexCleveland27.54
City Of CantonCanton25.4
Middletown Wastewater Treatment PlantMiddletown21.19
City Of Euclid, Wastewater Treatment PlantEuclid18.11
City Of Springfield Wastewater TreatmentSpringfield17.12
Maumee River Wastewater Treatment PlantWaterville15.06
Gary L Kron Water Reclamation FacilityMentor14.71
Lima WWTPLima14.49
Western Regional WRFWest Carrollton14.48
Rocky River Wastewater Treatment PlantRocky River13.54
City Of Warren Water Pollution ControlWarren13.31
Muddy Creek WWTPCincinnati12.73
Black River Wastewater Treatment PlantLorain12.3
Massillon WWTPMassillon11.5
Sandusky WPCSandusky11.27
Lesourdsville Water Reclamation FacilityHamilton11.24
North Regional Wastewater Treatment Plan (0857143037)Dayton11.24
Mansfield Wastewater Treatment PlantMansfield10.98
Upper Mill Creek Water Reclamation FacilWest Chester10.8
Beavercreek WRRFDayton9.73
Findlay WPCFFindlay9.51
Medina County - Liverpool WWTP (sd #500)Valley City9.15
Hamilton Water Reclamation FacilityHamilton8.62
Eastern Regional Water Reclamation FacilityKettering8.51
City Of Zanesville Wastewater Treatment PlantZanesville8.44
Newark WWTPNewark8.3
Sycamore Creek WWTPCincinnati8.08
City Of Elyria Wastewater Pollution Control PlantElyria7.97
Marion WPCMarion7.91
Sugarcreek WRFSpring Valley7.88
Lower East Fork Regional WWTPMilford7.83
Mason WWTP No 2Mason7.31
Fremont WPCFFremont7.22
Lower Little Miami WWTPMaineville6.9
French Creek WWTPNorth Ridgeville6.82
Lakewood WWTPLakewood6.28
North Olmsted WWTPNorth Olmsted6.03
Wooster Renewable EnergyWooster6
Willoughby-Eastlake Water Pollution ContEastlake5.93
Oregon Wastewater Treatment PlantOregon5.86
Alum Creek WWTPDelaware5.81
Fairfield WWTPFairfield5.55
Lancaster Water Pollution ControlLancaster5.38
Marysville WRFMarysville5.36
Barberton WPCFBarberton5.34
Alliance Water Tr. Plant And Wastewater Tr. PlantAlliance5.28
Troy WWTPTroy5.28
Upper Olentangy Water Reclamation CenterDelaware5.21
Middle East Fork Regional WWTPBatavia5.12
Polk Run WWTPLoveland5.12
Niles WWTPNiles5.01
Bowling GreenBowling Green5
Ashtabula WPCPAshtabula4.86
Perrysburg WWTPPerrysburg4.72
Avon Lake WPCFAvon Lake4.71
Sidney WWTPSidney4.66
Fairborn Water Reclamation CenterHuber Hts4.64
Struthers WWTPStruthers4.63
Wapakoneta WWTPWapakoneta4.58
Olentangy Environmental Control CenterPowell4.58
Portsmouth Lawson Run WWTPPortsmouth4.57
Trumbull Mosquito Creek WWTPWarren4.55
Fostoria City DumpFostoria4.28
Boardman WWTPYoungstown3.95
City Of Solon Water Reclamation FacilitySolon3.9
Erie County Sawmill Creek WWTPHuron3.82
Piqua WWTPPiqua3.72
Meander WPCFMineral Ridge3.72
Madison WWTP No 1Madison3.61
Lebanon WWTPLebanon3.6
Mount Vernon Wastewater Treatment PlantMount Vernon3.58
Wadsworth WWTPWadsworth3.58
Ashland WWTPAshland3.54
Tiffin WWTPTiffin3.37
London WWTPLondon3.31
City Of Twinsburg WWTPTwinsburg3.27
Taylor Creek WWTPCleves3.21
Painesville WPC PltPainesville3.16
Wilmington WWTPWilmington3.16
Miamisburg Water Reclamation FacilityMiamisburg3.13
Washington Court House WWTPWashington Court House3.12
Girard WWTPGirard3.06
Streetsboro Hudson Regional WWTPStreetsboro3
Upper Tuscarawas WWTP No 36Akron2.93
Defiance Water Pollution Control PlantDefiance2.87
Xenia Ford Road Wastewater Treatment PlantXenia2.83
City Of Salem - Wastewater PlantSalem2.82
Pickerington WWTPPickerington2.8
Oxford WWTPOxford2.79
Chillicothe WWTP - EasterlyChillicothe2.75
East Liverpool WWTPEast Liverpool2.73
Eastern Ohio Regional WW AuthorityBellaire2.71
Bellefontaine WWTPBellefontaine2.68
City Of Cambridge Water Pollution Control CenterCambridge2.55
Galion WWTPGalion2.55
Bucyrus WWTPBucyrus2.54
Norwalk WWTPNorwalk2.5
Kenton WWTPKenton2.47
Englewood WWTPEnglewood2.46
Van Wert WWTPVan Wert2.44
Conneaut WWTPConneaut2.44
Kent Water Reclamation FacilityKent2.41
Philip Q Maiorana WWTPLorain2.36
Springboro WWTPSpringboro2.33
Southwest Licking W & Sd Gale Rd Envir Ctrl FacHebron2.33
Orrville WWTPOrrville2.31
Indian Lake Regional WWTPRussells Point2.27
North Royalton WWTP ANorth Royalton2.25
Bedford WWTPBedford2.23
Athens WWTPAthens2.23
O'Bannon Creek Regional WWTPLoveland2.22
Fairfield Co Tussing Road WWTPLancaster2.2
Glady Run WWTPXenia2.12
Celina WWTPCelina2.01
New Philadelphia WWTPNew Philadelphia1.95
Port Clinton WWTPPort Clinton1.93
Amherst WpccAmherst1.91
Greenville WWTPGreenville1.91
Medina Co Sd #300 Hinckley WWTPHinckley1.89
Shawnee No 2 WWTPLima1.89
Jackson WWTPJackson1.88
Bedford Hts City OfBedford Heights1.83
Willard WPCPWillard1.81
Louisville WWTPLouisville1.8
Shelby WWTPShelby1.79
Saint Henry WWTPSt Henry1.79
Twin City WWTPUhrichsville1.77
Minster WWTPMinster1.77
Clyde WWTPClyde1.75
Napoleon WWTPNapoleon1.7
Canal Winchester WWTPCanal Winchester1.67
Urbana WPCFUrbana1.67
St Marys City WWTPSaint Marys1.66
Hubbard WPCFHubbard1.63
Ravenna WWTP & Sewer SystemRavenna1.61
Campbell WWTPCampbell1.58
Archbold VillageArchbold1.55
City Of Bryan Wastewater Treatment PlantBryan1.53
Eaton WWTPEaton1.53
Nine Mile Creek WWTPNew Richmond1.52
Circleville WWTPCircleville1.52
Upper Sandusky WWTPUpper Sandusky1.51
Ironton WWTPIronton1.51
Southwest Regional WWTPMedway1.46
West Carrollton WWTPW Carrollton1.45
Mcfarland Creek WWTPBainbridge1.42
Oberlin Water Environment Protection FacilityOberlin1.39
Wellston WWTP NorthWellston1.38
City Of Vermilion WPCFVermilion1.37
Hillsboro WWTPHillsboro1.35
City Of Coshocton WWTPCoshocton1.34
City Of Dover Wastewater Treatment PlantDover1.27
West Jefferson WWTPWest Jefferson1.24
Newton Falls WPCNewton Falls1.22
Gallipolis WPCFGallipolis1.22
Delphos WWTPDelphos1.21
Brookfield WWTPMasury1.18
Logan WWTPLogan1.18
Franklin Hills WWTPKent1.16
Heath WWTPHeath1.16
Ottawa WWTPOttawa1.16
Buckeye Lake WWTPBuckeye Lake1.15
Coldwater WWTPColdwater1.13
Huron Basin WWTPHuron1.12
Rittman WWTPRittman1.11
Danbury Twp WWTPPort Clinton1.11
Heatherstone WWTPPainesville1.11
Geneva WWTPGeneva1.08
Harrison WWTPHarrison1.08
Aurora Westerly WWTPAurora1.07
Sd No 7 Water Reclamation PlantMarion1.07
Brookville WWTPBrookville1.07
Aqua Ohio Water Co Inc - Blacklick WWTPColumbus1.06
City Of Bellevue WWTPBellevue1.03
Pataskala WWTPPataskala1.02
Leipsic WWTPLeipsic1
South Point VillageSouth Point1
Columbiana WWTPColumbiana0.98
Sunbury WWTPSunbury0.97
Gambier WWTPGambier0.97
American-Bath WWTPLima0.96
Chillicothe Correctional InstitutionChillicothe0.95
Union WWTPUnion0.94
Crestline WWTPCrestline0.94
Chagrin Falls Meadow Lane WWTPChagrin Falls0.93
Greenfield WWTPGreenfield0.91
Aurora Central WWTPAurora0.91
Wheelersburg WWTP Sd No 2Wheelersburg0.9
Sebring WWTPSebring0.89
Indian Creek WWTPNorth Bend0.88
Strongsville B WWTPStrongsville0.86
Oak Harbor WWTPOak Harbor0.86
New Lexington WWTPNew Lexington0.85
Strongsville Cwwtp & SewersStrongsville0.84

Page

1
2345

Wastewater treatment in Ohio: 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 · FOG · Equalization tank · 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 Ohio.” Updated October 26, 2026. https://klarifi.io/facilities/ohio

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

Try Klarifi for free

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

Try for free