How much wastewater does Iselin STP treat?

Iselin STP treats an average of 0.007 MGD and is permitted for a design flow of 0.04 MGD.

What treatment technology does Iselin STP use?

Klarifi has identified uncovered lagoons at the Heilwood facility.

What is the NPDES permit for Iselin STP?

The facility discharges under NPDES permit PA0092533, currently effective, expiring August 2030.

Is Iselin STP in compliance?

Discharge monitoring reports show 10 violations at Iselin STP in the last three years, 10 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Iselin STP and how do I contact them?

Iselin STP is a publicly owned treatment works in Heilwood, Pennsylvania. Klarifi lists 1 verified decision-maker contact for this facility, available with a free trial.

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Iselin STP

Heilwood, PA · Indiana County · Publicly Owned Treatment Works

Average flow: 0.007 MGD

Design flow: 0.04 MGD

NPDES permit: PA0092533; Effective

Permit expires: August 2030

Population served: —; CWNS 2022

Iselin STP is a publicly owned wastewater treatment works in Heilwood, Indiana County, Pennsylvania treating an average of 0.007 million gallons per day against a permitted design capacity of 0.04 MGD. Treatment on site includes uncovered lagoons. It discharges under NPDES permit PA0092533 (effective), which expires in August 2030, with 10 recorded violations in the last three years.

Treatment technology

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

Uncovered lagoons

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Compliance snapshot (last 3 years)

Total violations: 10

Effluent violations: 10

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

Key contacts

1 verified contact for Iselin STP, with validated emails and direct phone numbers.

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

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Iselin 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 September 11, 2026; facility record last updated August 13, 2026.

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