Who issues NPDES permits in Ohio?

Ohio Environmental Protection Agency issues and enforces NPDES permits for wastewater discharges in Ohio. Klarifi tracks 837 permits held by publicly owned treatment plants in the state.

How many NPDES permits in Ohio are expired or administratively continued?

49 permits are administratively continued (the plant applied for renewal and the old permit stays in force) and 27 are recorded as expired, out of 837 permits tracked. 760 are effective.

How many Ohio wastewater permits come up for renewal soon?

114 in 2026, 186 in 2027 and 167 in 2028. Each year has its own renewal calendar with the plants listed.

How do I look up an NPDES permit number?

Enter the permit number (two letters and seven characters, for example TX0021873) or the plant name in the lookup on the NPDES page; each result opens the plant profile with status, expiry, design flow and the three-year violation count.

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NPDES permits in Ohio

Name: NPDES permits held by wastewater treatment plants in Ohio
Creator: Klarifi
License: https://klarifi.io/terms-of-service

837 permits held by publicly owned wastewater treatment plants · issued by Ohio EPA

Effective

760

Administratively continued

Expired

Total tracked

837

Ohio Environmental Protection Agency (Ohio EPA) runs the NPDES program in Ohio under delegation from EPA Region 5, issuing and enforcing the discharge permits listed here. Klarifi tracks 837 permits held by publicly owned treatment plants in the state, with status, expiry, design flow and three-year compliance for each. Agency website →

An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.

Permit renewals by year

2026: 114 permits →2027: 186 permits →2028: 167 permits →

2029: 148 permits

2030: 118 permits

2031: 87 permits

Largest permit holders in Ohio

The 25 largest publicly owned wastewater treatment plants in Ohio by permitted design flow, with NPDES permit number, status and expiry. Source: EPA ICIS-NPDES via Klarifi.
Facility	City	Avg flow (MGD)	Design (MGD)	NPDES permit	Status	Expires	Violations (3y)
Akron WRF	Akron	44.82	90	OH0023833	Effective	Aug 2028	0
Southerly Wastewater Treatment Plant	Lockbourne	82.1	—	OHL024741	Effective	Dec 2030	7
Southerly Wastewater Treatment Center	Cleveland	78.11	—	OHL024651	Effective	Dec 2030	3
City Of Dayton Water Reclamation Facility (0857100983)	Dayton	38.22	72	OH0024881	Effective	Apr 2027	17
Metropolitan Sewer Dis Little Miami WWTP	Cincinnati	21.87	55	OH0025453	Effective	Jun 2030	8
City Of Toledo Division Of Water Reclaimation	Toledo	39.6	—	OH0027740	Effective	Jan 2029	3
City Of Canton	Canton	20.5	39	OH0024350	Effective	May 2028	1
Neorsd Westerly Wwt Complex	Cleveland	18.52	35	OH0024660	Effective	Jun 2030	0
Waste Water Treatment Plant	Youngstown	20.84	35	OH0028223	Effective	Oct 2028	231
Hamilton Water Reclamation Facility	Hamilton	5.26	32	OH0025445	Effective	Oct 2026	7
Middletown Wastewater Treatment Plant	Middletown	11.69	26	OH0026522	Effective	Dec 2026	82
City Of Springfield Wastewater Treatment	Springfield	12.27	25	OH0027481	Effective	Feb 2030	39
Ashtabula WPCP	Ashtabula	2.72	24	OH0023914	Effective	Jun 2030	84
Mansfield Wastewater Treatment Plant	Mansfield	6.67	24	OH0026328	Effective	Mar 2030	428
Maumee River Wastewater Treatment Plant	Waterville	11.65	22.5	OH0034223	Effective	Dec 2027	15
Rocky River Wastewater Treatment Plant	Rocky River	8.3	22.5	OH0030503	Effective	Jan 2028	15
City Of Euclid, Wastewater Treatment Plant	Euclid	10.45	22	OH0031062	Effective	Aug 2029	14
Gary L Kron Water Reclamation Facility	Mentor	9.35	20	OH0043559	Effective	Mar 2027	29
Western Regional WRF	West Carrollton	7.67	20	OH0026638	Effective	Oct 2026	2
Lima WWTP	Lima	11.44	18.5	OH0026069	Effective	Jun 2028	35
City Of Zanesville Wastewater Treatment Plant	Zanesville	5.91	18	OH0028240	Effective	Mar 2028	12
Lakewood WWTP	Lakewood	11.52	18	OH0026018	Administratively continued	Jul 2026	5
Massillon WWTP	Massillon	8.87	17	OH0020516	Effective	May 2031	0
City Of Warren Water Pollution Control	Warren	10.13	16	OH0027987	Effective	Nov 2028	68
Upper Mill Creek Water Reclamation Facil	West Chester	8.34	16	OH0072087	Expired	Dec 2023	33

All 837 plants in Ohio →

NPDES permits 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 September 11, 2026.

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