How much wastewater does City Of Monmouth treat?

City Of Monmouth treats an average of 2.64 MGD.

What is the NPDES permit for City Of Monmouth?

The facility discharges under NPDES permit ILL036218, currently effective, expiring December 2030.

Is City Of Monmouth in compliance?

Discharge monitoring reports show 20 violations at City Of Monmouth in the last three years, 20 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates City Of Monmouth and how do I contact them?

City Of Monmouth is a publicly owned treatment works in Monmouth, Illinois. Klarifi lists 1 verified decision-maker contact for this facility, available with a free trial.

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City Of Monmouth

Q: What treatment technology does City Of Monmouth use?

Klarifi has identified clarifiers, aerated lagoons, covered lagoons, uncovered lagoons, carrousels / oxidation ditches at the Monmouth facility.

Monmouth, IL · Warren County · Publicly Owned Treatment Works

Average flow: 2.64 MGD

Design flow: —

NPDES permit: ILL036218; Effective

Permit expires: December 2030

Population served: 8,886; CWNS 2022

City Of Monmouth is a publicly owned wastewater treatment plant in Monmouth, Warren County, Illinois treating an average of 2.64 million gallons per day, serving about 8,886 residents. Treatment on site includes clarifiers, aerated lagoons, covered lagoons, uncovered lagoons, carrousels / oxidation ditches. It discharges under NPDES permit ILL036218 (effective), which expires in December 2030, with 20 recorded violations in the last three years.

Treatment technology

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

Clarifiers

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Aerated lagoons

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Covered lagoons

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Uncovered lagoons

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Carrousels / oxidation ditches

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Compliance snapshot (last 3 years)

Total violations: 20

Effluent violations: 20

Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.

Key contacts

1 verified contact for City Of Monmouth, with validated emails and direct phone numbers.

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Names, validated emails and direct phone numbers for decision-makers at City Of Monmouth, plus the full compliance history and discharge data.

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City Of Monmouth: 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 March 29, 2025.

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