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City of Choteau

What EPA’s and Montana’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
1,691 people
Connections
717
Water source
Groundwater
Based in
Choteau, MT
County
Teton
Owner
Local government
Hardness
Very hard
The ZIP code it serves

59422

The short answer

2 results are above the health goal. The worst: Lead, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2001 to 2026.

Uranium, haloacetic acids (HAA5), fluoride, total trihalomethanes (TTHM), nitrate, arsenic and chromium (total): Montana’s own results, samples taken from Aug. 13, 2020 to Aug. 13, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

4.0ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 4.0 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Uranium

Comes from the source

Above the health goal

1.0ppb

Highest yearly average, 2021 to 2025

2025 average: 0.7 ppb

Averaged by year, the highest was 1.0 ppb, in 2024: below EPA’s legal limit of 30 ppb, but above its health goal of zero. In 2025, the latest year on file, its two samples averaged 0.7 ppb.

What handles it

Below EPA’s limits4

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

5.6ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 5.6 ppb, in 2021, below EPA’s legal limit of 60 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 8.9 ppb, in 2019.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.3ppm

Highest yearly average, 2021 to 2024

2024 average: 0.3 ppm

Averaged by year, the highest was 0.3 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. In 2024, the latest year on file, its two samples averaged 0.3 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.3 ppm, in 2016.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

4.8ppb

Highest yearly average, 2020 to 2026

2026, one sample: 2.1 ppb

Averaged by year, the highest was 4.8 ppb, in 2022, below EPA’s legal limit of 80 ppb. Its highest single sample was 8.1 ppb. In 2026, the latest year on file, its one sample was 2.1 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.2 ppb, in 2019.

What handles it

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

Nitrate

Comes from the source

Below EPA’s limits

0.55ppm

Highest sample; found in 2 of 2

2024 average: 0.4 ppm

The highest sample, in 2024, was 0.55 ppm, below EPA’s legal limit of 10 ppm. That is the only year on file, and its two samples averaged 0.4 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.61 ppm, in 2018.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best water filters for lead, ranked

Hardness

Very hard, typically 337 mg/L (19.7 grains per gallon), across 2 sampling points, in 2024.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 19.7 grains per gallon, salt includedSoftener or salt-free conditioner?Montana water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Uranium, haloacetic acids (HAA5), fluoride, total trihalomethanes (TTHM), nitrate, arsenic and chromium (total) results here are Montana’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of Choteau’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; Montana’s results run from Aug. 13, 2020 to Aug. 13, 2026.

Testing your own tap

City of Choteau’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 Montana certifies.

No lab Montana certifies is within 75 miles of the area City of Choteau serves on the state’s list. Some take samples by mail; the state’s page lists them all.

Montana State Environmental Laboratory: Private well testing packages for bacteria, metals, nutrients, anions, organic chemicals and more, open to the public. Samples can be mailed, sent by the lab's free courier, or dropped off at the lab. Environmental Laboratory, Montana Department of Public Health and Human Services.

All 36 certified labs for Montana

Sources

PWSID MT0000175. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Teton County

All Montana utilities

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