What is the address of City Of Monmouth?

The address on the plant’s EPA facility record is Rural Route 2 Highway 67 North, Monmouth, IL 61462, in Warren County. Its coordinates are 40.9452, -90.6401. For some plants the record holds the utility’s mailing address rather than the plant gate.

How much wastewater does City Of Monmouth treat?

City Of Monmouth treats an average of 3.88 MGD.

What treatment technology does City Of Monmouth use?

Klarifi has identified 5 treatment structures and unit processes at the Monmouth facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

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 19 violations at City Of Monmouth in the last three years, 19 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.

Try for free Log in

City Of Monmouth

Rural Route 2 Highway 67 North, Monmouth, IL 61462 · Warren County · Publicly Owned Treatment Works

Average flow: 3.88 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 3.88 million gallons per day, serving about 8,886 residents. It discharges under NPDES permit ILL036218 (effective), which expires in December 2030, with 19 recorded violations in the last three years.

Treatment technology

5 treatment structures and unit processes identified at City Of Monmouth.

Available with a free Klarifi account

See the full treatment train at City Of Monmouth: structures, unit processes and planned upgrades, with exact unit counts.

Create a free account

Compliance snapshot (last 3 years)

Total violations: 19

Effluent violations: 19

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.

Unlock 1 verified contact

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

Try Klarifi free

Nearby wastewater treatment plants in Illinois

Monmouth Main STP

Monmouth · 2 mi away

—

Kirkwood Stp, Village Of

Kirkwood · 8 mi away

0.18 MGD

Alexis STP

Alexis · 9 mi away

0.23 MGD

Galesburg Sanitary District STP

Galesburg · 12 mi away

7.4 MGD

Biggsville Stp, Village Of

Biggsville · 13 mi away

0.02 MGD

Abingdon Stp, City Of

Abingdon · 17 mi away

0.6 MGD

Aledo South Stp, City Of

Aledo · 17 mi away

0.3 MGD

Knoxville STP

Knoxville · 19 mi away

—

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 October 26, 2026; facility record last updated March 29, 2025.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Oxidation ditch · Anaerobic digester · all terms

Try Klarifi for free

Create your own trial account and explore how Klarifi can help you.

Try for free