What is the address of Mason City Stp, City Of?

The address on the plant’s EPA facility record is 1.5 Miles South Of Mason City, Mason City, IL 62664, in Mason County. Its coordinates are 40.1793, -89.7008. For some plants the record holds the utility’s mailing address rather than the plant gate.

How much wastewater does Mason City Stp, City Of treat?

Mason City Stp, City Of treats an average of 0.25 MGD.

What treatment technology does Mason City Stp, City Of use?

Klarifi has identified 3 treatment structures and unit processes at the Mason City facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

What is the NPDES permit for Mason City Stp, City Of?

The facility discharges under NPDES permit ILL029815, currently effective, expiring December 2030.

Is Mason City Stp, City Of in compliance?

Discharge monitoring reports show no violations at Mason City Stp, City Of in the last three years.

Who operates Mason City Stp, City Of and how do I contact them?

Mason City Stp, City Of is a publicly owned treatment works in Mason City, Illinois. Klarifi lists 2 verified decision-maker contacts for this facility, available with a free trial.

Try for free Log in

Mason City Stp, City Of

1.5 Miles South Of Mason City, Mason City, IL 62664 · Mason County · Publicly Owned Treatment Works

Average flow: 0.25 MGD

Design flow: —

NPDES permit: ILL029815; Effective

Permit expires: December 2030

Population served: 3,136; CWNS 2022

Mason City Stp, City Of is a publicly owned wastewater treatment works in Mason City, Mason County, Illinois treating an average of 0.25 million gallons per day, serving about 3,136 residents. It discharges under NPDES permit ILL029815 (effective), which expires in December 2030, with 0 recorded violations in the last three years.

Treatment technology

3 treatment structures and unit processes identified at Mason City Stp, City Of.

Available with a free Klarifi account

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

Create a free account

Compliance snapshot (last 3 years)

Total violations: 0

Effluent violations: 0

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

Key contacts

2 verified contacts for Mason City Stp, City Of, with validated emails and direct phone numbers.

Unlock 2 verified contacts

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

Try Klarifi free

Nearby wastewater treatment plants in Illinois

Easton STP

Easton · 9 mi away

0.14 MGD

San Jose Stp, Village Of

San Jose · 10 mi away

0.03 MGD

Green Valley STP

Green Valley · 13 mi away

0.02 MGD

Petersburg Stp, City Of

Petersburg · 13 mi away

0.31 MGD

Delavan Stp, City Of

Delavan · 15 mi away

0.37 MGD

Athens Stp, City Of

Athens · 16 mi away

0.22 MGD

Manito Stp, Village Of

Manito · 18 mi away

0.06 MGD

Williamsville East Stp, Village Of

Williamsville · 18 mi away

0.22 MGD

Mason City Stp, City Of: 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 6, 2025.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Ozonation · Activated sludge · all terms

Try Klarifi for free

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

Try for free