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Mobile City 3

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
40 people
Connections
40
Water source
Surface water bought from another system
Based in
Helena, MT
County
Lewis and Clark
Owner
Private
The ZIP code it serves

59601

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: Haloacetic acids (HAA5), 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 2021 to 2025.

Haloacetic acids (HAA5) and total trihalomethanes (TTHM): Montana’s own results, samples taken from Aug. 29, 2022 to Aug. 17, 2026.

Above the limit’s level, no violation recorded1

Haloacetic acids (HAA5)

Forms or is added in treatment

Above the limit’s level, no violation

61ppb

Highest yearly average, 2022 to 2026

2026 average: 52 ppb

Averaged by year, the highest was 61 ppb, in 2022, above EPA’s legal limit of 60 ppb. Its highest single sample was 84 ppb. In 2026, the latest year on file, its three samples averaged 52 ppb. EPA judges this limit on running averages at each sampling point, and recorded no violation for haloacetic acids (HAA5) 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.

What handles it

No certification claim covers this compound yet.

Above the health goal1

Lead

Comes from pipes, often your own

Above the health goal

2.0ppb

90th percentile, 2023 to 2025

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 limits1

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

49.8ppb

Highest yearly average, 2022 to 2026

2026 average: 44.3 ppb

Averaged by year, the highest was 49.8 ppb, in 2025, below EPA’s legal limit of 80 ppb. Its highest single sample was 66 ppb. In 2026, the latest year on file, its three samples averaged 44.3 ppb.

What handles it

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

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 5 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Haloacetic acids (HAA5) and total trihalomethanes (TTHM) results here are Montana’s own from 2022 on, with EPA’s national file for 2012 to 2019. Mobile City 3’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. 29, 2022 to Aug. 17, 2026.

Testing your own tap

Mobile City 3’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 Mobile City 3 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 · under a mile

    Certified for bacteria, minerals and other inorganics, organic chemicals

    (406) 444-3444

  • Alpine Analytical

    Helena, MT · under a mile

    Certified for bacteria, minerals and other inorganics

    (406) 449-6282

  • Energy Laboratories, Inc.

    Helena, MT · about 10 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 MT0005088. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Lewis and Clark County

All Montana utilities

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