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Still River Estates Subdivision

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
188 people
Connections
33
Water source
Groundwater
Based in
Billings, MT
County
Yellowstone
Owner
Private
The ZIP code it serves

59106

The short answer

1 result is above EPA’s legal limit, and 3 more are above the health goal. The worst: Nitrate, above the legal limit. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2023 to 2026.

Nitrate, uranium, arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total): Montana’s own results, samples taken from Feb. 1, 2023 to Sept. 3, 2026.

Above the legal limit1

Nitrate

Comes from the source

Above the legal limit

10.7ppm

Highest sample; found in 31 of 31

2026 average: 6.7 ppm

One sample, in 2023, was above EPA’s legal limit of 10 ppm, at 10.7 ppm. The next sample at the same point, within 30 days, kept the average above the limit. In 2026, the latest year on file, its 14 samples averaged 6.7 ppm. EPA recorded a violation for nitrate at this utility in 2023.

What handles it

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

Above the health goal3

Uranium

Comes from the source

Above the health goal

17.1ppb

Highest yearly average, 2023

Averaged by year, the highest was 17.1 ppb, in 2023: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 17.3 ppb. That is the only year on file.

What handles it

Lead

Comes from pipes, often your own

Above the health goal

8.0ppb

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 8.0 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

Arsenic

Comes from the source

Above the health goal

1.0ppb

Highest yearly average, 2023

Averaged by year, the highest was 1.0 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. That is the only year on file.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits3

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

42.5ppb

Highest yearly average, 2023 to 2026

2026 average: 14.5 ppb

Averaged by year, the highest was 42.5 ppb, in 2023, below EPA’s legal limit of 80 ppb. Its highest single sample was 56 ppb. In 2026, the latest year on file, its two samples averaged 14.5 ppb.

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

12ppb

Highest yearly average, 2023 to 2026

2026, one sample: 2.9 ppb

Averaged by year, the highest was 12 ppb, in 2023, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, its one sample was 2.9 ppb.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.4ppm

Highest yearly average, 2023

Averaged by year, the highest was 0.4 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. That is the only year on file.

What handles it

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

  • NSF/ANSI 53

    Claims: Nitrate/Nitrite (30 ppm challenge), Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Lead, Arsenic

    Other certifiers’ wording: Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Uranium, Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Nitrate, Uranium, Lead, Arsenic

    Other certifiers’ wording: Nitrate; Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

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 reverse osmosis systems, ranked

The best water filters for lead, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Nitrate-NitriteA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJan. 1, 2023 to March 31, 202310.7 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 25 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Nitrate, uranium, arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total) results here are Montana’s own from 2023 on, with EPA’s national file for 2012 to 2019. Still River Estates Subdivision’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 Feb. 1, 2023 to Sept. 3, 2026.

Testing your own tap

Still River Estates Subdivision’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 lab Montana certifies closest to the area Still River Estates Subdivision serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Energy Laboratories, Inc.

    Billings, MT · about 8 miles

    Certified for bacteria, minerals and other inorganics, organic chemicals

    (800) 735-4489

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 MT0005118. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Yellowstone County

All Montana utilities

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