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Irwin Municipal Supply

What EPA’s and Iowa’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
313 people
Connections
177
Water source
Groundwater bought from another system
Based in
Irwin, IA
County
Shelby
Owner
Local government
The ZIP code it serves

51446

The short answer

Nothing in EPA’s and Iowa’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): Iowa’s own results, samples taken from Aug. 9, 2022 to Aug. 18, 2025, with EPA’s 2012 to 2019 file for earlier years.

Below EPA’s limits2

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

35ppb

Highest yearly average, 2022 to 2025

2025, one sample: 29 ppb

Averaged by year, the highest was 35 ppb, in 2022, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, its one sample was 29 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 37 ppb, in 2013.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

19ppb

Highest yearly average, 2022 to 2025

Averaged by year, the highest was 19 ppb, in 2025, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.0 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Lead

Violations since 2016

No health-based violations on file with EPA since 2016. There are 6 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Iowa’s own from 2022 on, with EPA’s national file for 2012 to 2019. Irwin Municipal Supply’s own annual report, which it must send you every year, has the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; Iowa’s results run from Aug. 9, 2022 to Aug. 18, 2025.

Testing your own tap

Irwin Municipal Supply’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab Iowa certifies.

The 3 labs Iowa certifies closest to the area Irwin Municipal Supply serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Midwest Laboratories

    Omaha, NE · about 61 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics

    (402) 334-7770

  • Foundation Analytical Laboratory

    Cherokee, IA · about 70 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, PFAS

    (712) 225-6989

  • Analytical & Consulting Services

    Sergeant Bluff, IA · about 71 miles

    Certified for bacteria, nitrate

    (712) 943-4888

State Hygienic Laboratory at the University of Iowa: Through the Grants-to-Counties program, private well owners in participating counties can have their water tested for total coliform bacteria and nitrate. Start with the county sanitarian at your county health department. No cost in a participating county. The Grants-to-Counties Program, State Hygienic Lab at the University of Iowa.

All 36 certified labs for Iowa

Sources

PWSID IA8340099. Rebuilt from EPA data on Oct. 18, 2026.

Also in Shelby County

All Iowa utilities

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