Skip to content
TapBuff
ZIP

Arapahoe WC

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
99 people
Connections
56
Water source
Groundwater
Based in
Arapahoe, CO
County
Cheyenne
Owner
Private
The ZIP code it serves

80802

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, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5): Colorado’s own results, samples taken from April 6, 2020 to March 23, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

4.0ppb

Highest yearly average, 2022

Averaged by year, the highest was 4.0 ppb, in 2022: below EPA’s legal limit of 10 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 2013.

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

9.7ppb

Highest yearly average, 2025

Averaged by year, the highest was 9.7 ppb, in 2025: below EPA’s legal limit of 30 ppb, but above its health goal of zero. Its highest single sample was 11.9 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 9.8 ppb, in 2013.

What handles it

Below EPA’s limits3

Nitrate

Comes from the source

Below EPA’s limits

4.9ppm

Highest sample; found in 12 of 12

2026 average: 3.9 ppm

The highest sample, in 2024, was 4.9 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its two samples averaged 3.9 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 5.2 ppm, in 2017.

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

0.61ppm

Highest yearly average, 2022

Averaged by year, the highest was 0.61 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.65 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.91 ppm, in 2012.

What handles it

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

0.6ppb

Highest yearly average, 2021 to 2024

2024, one sample: 0.6 ppb

Averaged by year, the highest was 0.6 ppb, in 2021, below EPA’s legal limit of 80 ppb. In 2024, the latest year on file, its one sample was 0.6 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.9 ppb, in 2012.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Haloacetic acids (HAA5)
  • 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 11 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, uranium, nitrate, fluoride, total trihalomethanes (TTHM), chromium (total) and haloacetic acids (HAA5) results here are Colorado’s own from 2020 on, with EPA’s national file for 2012 to 2019. Arapahoe WC’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 April 6, 2020 to March 23, 2026.

Testing your own tap

Arapahoe WC’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.

No lab Colorado certifies is within 75 miles of the area Arapahoe WC serves on the state’s list. Some take samples by mail; the state’s page lists them all.

All 54 certified labs for Colorado

Sources

PWSID CO0109001. Rebuilt from EPA data on Oct. 18, 2026.

Nearby

All Colorado utilities

What to do next