Saint Henry WWTP
Cooper Ave, St Henry, OH 45883 · Mercer County · Publicly Owned Treatment Works
- Average flow
- 1.79 MGD
- Design flow
- 0.87 MGD
- NPDES permit
- OH0020028
- Effective
- Permit expires
- February 2028
- Population served
- 4,339
- CWNS 2022
Saint Henry WWTP is a publicly owned wastewater treatment works in St Henry, Mercer County, Ohio treating an average of 1.79 million gallons per day against a permitted design capacity of 0.87 MGD, serving about 4,339 residents. It discharges under NPDES permit OH0020028 (effective), which expires in February 2028, with 4 recorded violations in the last three years.
Treatment technology
2 treatment structures and unit processes identified at Saint Henry WWTP.
Available with a free Klarifi account
See the full treatment train at Saint Henry WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 4
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Saint Henry WWTP.
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Coldwater · 4 mi away
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Chickasaw · 7 mi away
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Celina · 7 mi away
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Celina · 8 mi away
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Ft Recovery · 8 mi away
0.14 MGD
New Bremen · 13 mi away
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Saint Henry WWTP: frequently asked 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; facility record last updated November 8, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Significant industrial user · WWTP · all terms