How much wastewater does Onawa City Of STP treat?

Onawa City Of STP treats an average of 0.22 MGD and is permitted for a design flow of 0.85 MGD.

What treatment technology does Onawa City Of STP use?

Klarifi has identified one treatment structure or unit process at the Onawa facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

What is the NPDES permit for Onawa City Of STP?

The facility discharges under NPDES permit IA0036145, currently administratively continued, expiring April 2008.

Is Onawa City Of STP in compliance?

Discharge monitoring reports show 41 violations at Onawa City Of STP in the last three years, 41 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Onawa City Of STP and how do I contact them?

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

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Onawa City Of STP

Onawa, IA 51040 · Monona County · Publicly Owned Treatment Works

Average flow: 0.22 MGD

Design flow: 0.85 MGD

NPDES permit: IA0036145; Administratively continued

Permit expires: April 2008

Population served: 2,906; CWNS 2022

Onawa City Of STP is a publicly owned wastewater treatment works in Onawa, Monona County, Iowa treating an average of 0.22 million gallons per day against a permitted design capacity of 0.85 MGD, serving about 2,906 residents. It discharges under NPDES permit IA0036145 (administratively continued), which expires in April 2008, with 41 recorded violations in the last three years.

Treatment technology

One treatment structure or unit process identified at Onawa City Of STP.

Available with a free Klarifi account

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

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Compliance snapshot (last 3 years)

Total violations: 41

Effluent violations: 41

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

Key contacts

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

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

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Nearby wastewater treatment plants in Iowa

Blencoe City Of STP

Blencoe · 6 mi away

0.01 MGD

Whiting City Of STP

Whiting · 8 mi away

0.05 MGD

Moorhead City Of STP

Moorhead · 14 mi away

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Little Sioux River Sioux STP

Little Sioux · 14 mi away

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Hornick City Of STP

Hornick · 15 mi away

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Pisgah City Of STP

Pisgah · 15 mi away

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Soldier City Of STP

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Smithland City Of STP

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Onawa City Of STP: 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 May 17, 2025.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · WWTP · Biosolids · all terms

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