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Town of Denton

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
255 people
Connections
169
Water source
Surface water
Based in
Denton, MT
County
Fergus
Owner
Local government
The ZIP code it serves

59430

The short answer

2 results are above the health goal. The worst: Lead, above the health goal. 77 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2001 to 2025.

Uranium, nitrate, fluoride, total trihalomethanes (TTHM), haloacetic acids (HAA5), arsenic and chromium (total): Montana’s own results, samples taken from Feb. 11, 2020 to Sept. 9, 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, 2023 to 2025

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

1.8ppb

Highest yearly average, 2022

Averaged by year, the highest was 1.8 ppb, in 2022: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.0 ppb, in 2014.

What handles it

Below EPA’s limits4

Nitrate

Comes from the source

Below EPA’s limits

7.1ppm

Highest sample; found in 28 of 28

2026 average: 3.7 ppm

The highest sample, in 2020, was 7.1 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its three samples averaged 3.7 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 21.1 ppm, in 2015, and EPA recorded violations in 2012 and 2016.

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

1.1ppm

Highest yearly average, 2021 to 2025

2025, one sample: 0.9 ppm

Averaged by year, the highest was 1.1 ppm, in 2021, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its one sample was 0.9 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.3 ppm, in 2015.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

4.5ppb

Highest yearly average, 2020 to 2026

2026, one sample: 4.0 ppb

Averaged by year, the highest was 4.5 ppb, in 2021, below EPA’s legal limit of 80 ppb. Its highest single sample was 9.0 ppb. In 2026, the latest year on file, its one sample was 4.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 7.7 ppb, in 2013.

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

3.0ppb

Highest yearly average, 2020 to 2026

2026, one sample: 1.3 ppb

Averaged by year, the highest was 3.0 ppb, in 2021, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, its one sample was 1.3 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.6 ppb, in 2013.

What handles it

No certification claim covers this compound yet.

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

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)May 1, 2026 to May 31, 2026—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Feb. 1, 2026 to Feb. 28, 2026—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Jan. 1, 2026 to Jan. 31, 2026—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Dec. 1, 2025 to Dec. 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Nov. 1, 2025 to Nov. 30, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Oct. 1, 2025 to Oct. 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Sept. 1, 2025 to Sept. 30, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Aug. 1, 2025 to Aug. 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)July 1, 2025 to July 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)June 1, 2025 to June 30, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)May 1, 2025 to May 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)April 1, 2025 to April 30, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)March 1, 2025 to March 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Feb. 1, 2025 to Feb. 28, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Jan. 1, 2025 to Jan. 31, 2025—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Dec. 1, 2024 to Dec. 31, 2024—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Nov. 1, 2024 to Nov. 30, 2024—Archived
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Oct. 1, 2024 to Oct. 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Sept. 1, 2024 to Sept. 30, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Aug. 1, 2024 to Aug. 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)July 1, 2024 to July 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)June 1, 2024 to June 30, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)May 1, 2024 to May 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)April 1, 2024 to April 30, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)March 1, 2024 to March 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Feb. 1, 2024 to Feb. 29, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Jan. 1, 2024 to Jan. 31, 2024—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Dec. 1, 2023 to Dec. 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Nov. 1, 2023 to Nov. 30, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Oct. 1, 2023 to Oct. 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Sept. 1, 2023 to Sept. 30, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Aug. 1, 2023 to Aug. 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)July 1, 2023 to July 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)June 1, 2023 to June 30, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)May 1, 2023 to May 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)April 1, 2023 to April 30, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)March 1, 2023 to March 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Feb. 1, 2023 to Feb. 28, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Jan. 1, 2023 to Jan. 31, 2023—Archived
Long Term 2 Enhanced Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Dec. 1, 2022 to Dec. 31, 2022—Archived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 12 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Uranium, nitrate, fluoride, total trihalomethanes (TTHM), haloacetic acids (HAA5), arsenic and chromium (total) results here are Montana’s own from 2020 on, with EPA’s national file for 2012 to 2019. Town of Denton’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. 11, 2020 to Sept. 9, 2026.

Testing your own tap

Town of Denton’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 Town of Denton serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Aqua Tech Laboratory

    Lewistown, MT · about 30 miles

    Certified for bacteria

    (406) 538-6988

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 MT0000199. Rebuilt from EPA data on Oct. 18, 2026.

Also in Fergus County

All Montana utilities

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