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Town of Arriba

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
216 people
Connections
159
Water source
Groundwater
Based in
Evans, CO
County
Lincoln
Owner
Local government
The ZIP code it serves

80804

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Arsenic, uranium, nitrate, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total): Colorado’s own results, samples taken from Jan. 14, 2020 to Oct. 5, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

6.0ppb

Highest yearly average, 2022 to 2026

2026, one sample: 5.0 ppb

Averaged by year, the highest was 6.0 ppb, in 2022: 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 5.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 6.0 ppb, in 2015.

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

6.5ppb

Highest yearly average, 2025

Averaged by year, the highest was 6.5 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. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 8.0 ppb, in 2019.

What handles it

Below EPA’s limits5

Nitrate

Comes from the source

Below EPA’s limits

8.4ppm

Highest sample; found in 28 of 28

2026 average: 7.5 ppm

The highest sample, in 2021, was 8.4 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its four samples averaged 7.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 8.6 ppm, in 2013.

What handles it

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

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

28ppb

Highest yearly average, 2020 to 2026

2026, one sample: 1.7 ppb

Averaged by year, the highest was 28 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its one sample was 1.7 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 38.9 ppb, in 2017.

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

5.7ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 5.7 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 13.3 ppb, in 2014.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.37ppm

Highest yearly average, 2020 to 2026

2026, one sample: 0.35 ppm

Averaged by year, the highest was 0.37 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2026, the latest year on file, its one sample was 0.35 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.4 ppm, in 2013.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

5.0ppb

Highest yearly average, 2022 to 2026

2026, one sample: 5.0 ppb

Averaged by year, the highest was 5.0 ppb, in 2024, below EPA’s legal limit of 100 ppb. In 2026, the latest year on file, its one sample was 5.0 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.0 ppb, in 2013.

What handles it

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

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

    For: Arsenic, Uranium

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

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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

Violations since 2016

No health-based violations on file with EPA since 2016. There are 2 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, uranium, nitrate, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total) results here are Colorado’s own from 2020 on, with EPA’s national file for 2012 to 2019. Town of Arriba’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. 14, 2020 to Oct. 5, 2026.

Testing your own tap

Town of Arriba’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 lab Colorado certifies closest to the area Town of Arriba serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Fort Morgan, City of

    Ft. Morgan, CO · about 66 miles

    Certified for bacteria

All 54 certified labs for Colorado

Sources

PWSID CO0137001. Rebuilt from EPA data on Oct. 18, 2026.

Also in Lincoln County

All Colorado utilities

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