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Walnut Municipal Utilities

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
768 people
Connections
420
Water source
Groundwater
Based in
Walnut, IA
County
Pottawattamie
Owner
Local government
The ZIP code it serves

51577

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), fluoride, arsenic, chromium (total), haloacetic acids (HAA5) and nitrate: Iowa’s own results, samples taken from July 22, 2020 to July 15, 2026, 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

50ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 50 ppb, in 2024, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 17 ppb, in 2017.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

2.2ppm

Highest yearly average, 2020 to 2026

2026, one sample: 1.9 ppm

Averaged by year, the highest was 2.2 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. In 2026, the latest year on file, its one sample was 1.9 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.1 ppm, in 2014.

What handles it

5 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Haloacetic acids (HAA5)
  • Lead
  • Nitrate

Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), fluoride, arsenic, chromium (total), haloacetic acids (HAA5) and nitrate results here are Iowa’s own from 2020 on, with EPA’s national file for 2012 to 2019. Walnut Municipal Utilities’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 July 22, 2020 to July 15, 2026.

Testing your own tap

Walnut Municipal Utilities’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 lab Iowa certifies closest to the area Walnut Municipal Utilities 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 50 miles

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

    (402) 334-7770

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 IA7872062. Rebuilt from EPA data on Oct. 18, 2026.

Also in Pottawattamie County

All Iowa utilities

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