How much wastewater does Saint Henry WWTP treat?

Saint Henry WWTP treats an average of 0.09 MGD and is permitted for a design flow of 0.87 MGD.

What treatment technology does Saint Henry WWTP use?

Klarifi has identified aerated lagoons, uncovered lagoons at the St Henry facility.

What is the NPDES permit for Saint Henry WWTP?

The facility discharges under NPDES permit OH0020028, currently effective, expiring February 2028.

Is Saint Henry WWTP in compliance?

Discharge monitoring reports show 3 violations at Saint Henry WWTP in the last three years, 1 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Saint Henry WWTP and how do I contact them?

Saint Henry WWTP is a publicly owned treatment works in St Henry, Ohio. Klarifi lists decision-maker contacts for this facility, available with a free trial.

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Saint Henry WWTP

St Henry, OH · Mercer County · Publicly Owned Treatment Works

Average flow: 0.09 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 0.09 million gallons per day against a permitted design capacity of 0.87 MGD, serving about 4,339 residents. Treatment on site includes aerated lagoons, uncovered lagoons. It discharges under NPDES permit OH0020028 (effective), which expires in February 2028, with 3 recorded violations in the last three years.

Treatment technology

Treatment structures identified at this facility. Exact unit counts are available in Klarifi.

Aerated lagoons

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Uncovered lagoons

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Compliance snapshot (last 3 years)

Total violations: 3

Effluent violations: 1

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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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 September 11, 2026; facility record last updated November 8, 2025.

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