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Rocky Mountain WUA

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
30 people
Connections
15
Water source
Groundwater
Based in
Clancy, MT
County
Jefferson
Owner
Private
The ZIP code it serves

59638

The short answer

1 result is above the limit’s level with no violation recorded, and 1 more is above the health goal. The worst: Uranium, above the limit’s level, no violation. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 1995 to 2026.

Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM): Montana’s own results, samples taken from Oct. 9, 2020 to April 20, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the limit’s level, no violation recorded1

Uranium

Comes from the source

Above the limit’s level, no violation

33ppb

Highest yearly average, 2020 to 2026

2026 average: 5.8 ppb

Averaged by year, the highest was 33 ppb, in 2020, above EPA’s legal limit of 30 ppb. In 2026, the latest year on file, its five samples averaged 5.8 ppb. EPA judges this limit on running averages at each sampling point, and recorded no violation for uranium at this utility since 2020. Results like these with no violation often include water sampled before treatment or blending; the utility’s annual report says what reaches the tap. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 11.7 ppb, in 2016. One result, 37,200 ppb on Dec. 18, 2025 in Montana’s results, is left out as a likely entry error: the typical result there is 27 ppb.

What handles it

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

2.0ppb

90th percentile, 2024 to 2026

In the latest period, 9 in 10 homes sampled were at or below 2.0 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

Below EPA’s limits2

Nitrate

Comes from the source

Below EPA’s limits

1.1ppm

Highest sample; found in 8 of 8

2026, one sample: 1.1 ppm

The highest sample, in 2026, was 1.1 ppm, below EPA’s legal limit of 10 ppm. That was also the latest year on file, and its one sample was 1.1 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.3 ppm, in 2012.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.2ppm

Highest yearly average, 2020

Averaged by year, the highest was 0.2 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.12 ppm, in 2013.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Total trihalomethanes (TTHM)

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

Violations since 2016

No health-based violations on file with EPA since 2016. There are 3 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Uranium, nitrate, fluoride, arsenic, chromium (total) and total trihalomethanes (TTHM) results here are Montana’s own from 2020 on, with EPA’s national file for 2012 to 2019. Rocky Mountain WUA’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 Oct. 9, 2020 to April 20, 2026.

Testing your own tap

Rocky Mountain WUA’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.

The 3 labs Montana certifies closest to the area Rocky Mountain WUA serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • DPHHS State of Montana Environmental Laboratory

    Helena, MT · about 16 miles

    Certified for bacteria, minerals and other inorganics, organic chemicals

    (406) 444-3444

  • Alpine Analytical

    Helena, MT · about 16 miles

    Certified for bacteria, minerals and other inorganics

    (406) 449-6282

  • Energy Laboratories, Inc.

    Helena, MT · about 19 miles

    Certified for bacteria, minerals and other inorganics, organic chemicals

    (406) 442-0711

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 MT0000058. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Jefferson County

All Montana utilities

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