Lagoon systems: wastewater treatment plants in Ohio
196 plants · 23% of the state · 259 MGD reported by 173 plants
Klarifi identifies 196 publicly owned wastewater treatment plants with lagoon systems in Ohio, 23% of the 843 plants in the state (259 MGD reported by 173 plants). The largest is Akron WRF in Akron at 59.62 MGD.
Lagoon systems treat wastewater in large earthen ponds over weeks of retention time, with or without mechanical aeration. They serve thousands of small towns because they are cheap to run, but they struggle with ammonia and nutrient limits, fill with sludge over decades and are the plants most often converted or upgraded when a permit is renewed.
The largest lagoons in Ohio
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Akron WRF | Akron | 59.62 | OH0023833 | Aug 2028 | 0 |
| 2 | Lima WWTP | Lima | 14.49 | OH0026069 | Jun 2028 | 35 |
| 3 | Upper Mill Creek Water Reclamation Facil | West Chester | 10.8 | OH0072087 | Dec 2023 | 37 |
| 4 | Beavercreek WRRF | Dayton | 9.73 | OH0025381 | Nov 2030 | 47 |
| 5 | Marion WPC | Marion | 7.91 | OH0026352 | Apr 2030 | 14 |
| 6 | Lower East Fork Regional WWTP | Milford | 7.83 | OH0049379 | Oct 2026 | 4 |
| 7 | Mason WWTP No 2 | Mason | 7.31 | OH0020494 | May 2026 | 0 |
| 8 | Wooster Renewable Energy | Wooster | 6 | OH0028185 | Nov 2029 | 23 |
| 9 | Alum Creek WWTP | Delaware | 5.81 | OH0121380 | Dec 2030 | 8 |
| 10 | Marysville WRF | Marysville | 5.36 | OH0136271 | Jun 2028 | 8 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Ohio
Lagoon systems in other states
Lagoon systems 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 · Biosolids · Sludge dewatering · Biological nutrient removal · all terms