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Somerset Domestic WD

What EPA’s and Colorado’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
100 people
Connections
63
Water source
Groundwater influenced by surface water
Based in
Somerset, CO
County
Gunnison
Owner
Local government
The ZIP code it serves

81434

The short answer

2 results are above EPA’s legal limit, and 2 more are above the health goal. The worst: Copper, above the action level. 20 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2025.

Total trihalomethanes (TTHM), arsenic, uranium, haloacetic acids (HAA5), fluoride, chromium (total) and nitrate: Colorado’s own results, samples taken from Jan. 7, 2020 to Aug. 3, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit2

Copper

Comes from pipes, often your own

Above the action level

2.2ppm

90th percentile, 2025

In the latest period, 9 in 10 homes sampled were at or below 2.2 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Above the legal limit

105ppb

Highest yearly average, 2020 to 2026

2026 average: 20.2 ppb

Averaged by year, the highest was 105 ppb, in 2020, above EPA’s legal limit of 80 ppb. Its highest single sample was 231 ppb. In 2026, the latest year on file, its three samples averaged 20.2 ppb. EPA recorded violations for total trihalomethanes (TTHM) at this utility in 2020 and 2023. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 149 ppb, in 2017, and EPA recorded violations in 2016, 2017, 2018 and 2019.

What handles it

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

Above the health goal2

Arsenic

Comes from the source

Above the health goal

3.5ppb

Highest yearly average, 2022 to 2026

2026, one sample: 3.0 ppb

Averaged by year, the highest was 3.5 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2026, the latest year on file, its one sample was 3.0 ppb.

What handles it

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

Uranium

Comes from the source

Above the health goal

0.3ppb

Highest yearly average, 2025

Averaged by year, the highest was 0.3 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That is the only year on file.

What handles it

Below EPA’s limits4

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

31.8ppb

Highest yearly average, 2020 to 2026

2026 average: 14.4 ppb

Averaged by year, the highest was 31.8 ppb, in 2023, below EPA’s legal limit of 60 ppb. Its highest single sample was 65.5 ppb. In 2026, the latest year on file, its three samples averaged 14.4 ppb. EPA recorded no violation for haloacetic acids (HAA5) at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 48 ppb, in 2015.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

1.1ppm

Highest yearly average, 2022 to 2025

2025, one sample: 0.17 ppm

Averaged by year, the highest was 1.1 ppm, in 2023, below EPA’s legal limit of 4.0 ppm. In 2025, the latest year on file, its one sample was 0.17 ppm.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

8.0ppb

Highest yearly average, 2022 to 2026

Averaged by year, the highest was 8.0 ppb, in 2026, below EPA’s legal limit of 100 ppb. That was also the latest year on file.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

0.1ppm

Highest sample; found in 3 of 4

2025: not found

The highest sample, in 2024, was 0.1 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, it wasn’t found in its one sample.

What handles it

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

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: Copper Reduction, Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Copper, Total trihalomethanes (TTHM), Arsenic

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

  • NSF/ANSI 58

    Claims: Copper Reduction, Trihalomethanes (TTHM) Reduction, Arsenic (Pentavalent)<=50 ppb Reduction, Uranium

    For: Copper, Total trihalomethanes (TTHM), Arsenic, Uranium

    Other certifiers’ wording: 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

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Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2023 to Dec. 31, 20230.084 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2023 to Sept. 30, 20230.082 MG/LResolved
Surface Water Treatment RuleRequired treatment for surface water or groundwater was not met.EPA: Treatment Technique (SWTR and GWR)Nov. 1, 2021 to Nov. 30, 2021—Resolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2020 to Dec. 31, 20200.089 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2020 to Sept. 30, 20200.089 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2020 to June 30, 20200.1 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2020 to March 31, 20200.093 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2019 to Dec. 31, 20190.095 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2019 to Sept. 30, 20190.092 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2018 to Sept. 30, 20180.086 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2018 to June 30, 20180.12 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2018 to March 31, 20180.12 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2017 to Dec. 31, 20170.15 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2017 to Sept. 30, 20170.15 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2017 to June 30, 20170.13 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2017 to March 31, 20170.14 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageOct. 1, 2016 to Dec. 31, 20160.13 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJuly 1, 2016 to Sept. 30, 20160.1 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageApril 1, 2016 to June 30, 20160.12 MG/LResolved
TTHMThe running average was above the legal limit.EPA: Maximum Contaminant Level Violation, AverageJan. 1, 2016 to March 31, 20160.093 MG/LResolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 18 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), arsenic, uranium, haloacetic acids (HAA5), fluoride, chromium (total) and nitrate results here are Colorado’s own from 2020 on, with EPA’s national file for 2012 to 2019. Somerset Domestic WD’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; Colorado’s results run from Jan. 7, 2020 to Aug. 3, 2026.

Testing your own tap

Somerset Domestic WD’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 Colorado certifies.

The 2 labs Colorado certifies closest to the area Somerset Domestic WD serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Mesa County Public Health Regional Laboratory

    Grand Junction, CO · about 57 miles

    Certified for bacteria

  • Eagle River W / S District

    Avon, CO · about 65 miles

    Certified for bacteria, lead and copper, metals, radioactivity

All 54 certified labs for Colorado

Sources

PWSID CO0126715. Rebuilt from EPA data on Oct. 18, 2026.

Also in Gunnison County

All Colorado utilities

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