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Moses Coulee Water Association

What EPA’s and Washington’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
42 people
Connections
17
Water source
Groundwater
Based in
Wenatchee, WA
County
Douglas
Owner
Private
Hardness
Hard
The ZIP code it serves

98850

The short answer

1 result is 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, fluoride, nitrate and chromium (total): Washington’s own results, samples taken from March 18, 2020 to May 5, 2026, with EPA’s 2012 to 2019 file for earlier years.

Haloacetic acids (HAA5) and total trihalomethanes (TTHM): EPA’s compliance monitoring file, samples taken from Aug. 18, 2013 to Oct. 20, 2014. Newer results are in the utility’s annual water quality report.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

1.3ppb

Highest yearly average, 2022

Averaged by year, the highest was 1.3 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 1.2 ppb, in 2018.

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 limits5

Fluoride

Forms or is added in treatment

Below EPA’s limits

1.2ppm

Highest yearly average, 2022

Averaged by year, the highest was 1.2 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.32 ppm, in 2014.

What handles it

Nitrate

Comes from the source

Below EPA’s limits

2.8ppm

Highest sample; found in 7 of 7

2026, one sample: 2.7 ppm

The highest sample, in 2025, was 2.8 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 2.7 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 2.6 ppm, in 2018.

What handles it

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

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

2.6ppb

Highest yearly average, 2013

Averaged by year, the highest was 2.6 ppb, in 2013, below EPA’s legal limit of 60 ppb. That is the only year on file.

What handles it

No certification claim covers this compound yet.

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

3.4ppb

Highest yearly average, 2013 to 2014

Averaged by year, the highest was 3.4 ppb, in 2014, below EPA’s legal limit of 80 ppb. That was also the latest year on file.

What handles it

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

Chromium (total)

Comes from the source

Below EPA’s limits

1.1ppb

Highest yearly average, 2022

Averaged by year, the highest was 1.1 ppb, in 2022, below EPA’s legal limit of 100 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.6 ppb, in 2014.

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

    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

Hardness

Hard, 165 mg/L (9.6 grains per gallon), at its one sampling point, in 2022.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 9.6 grains per gallon, salt includedSoftener or salt-free conditioner?Washington water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016. There are 83 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, fluoride, nitrate and chromium (total) results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Haloacetic acids (HAA5) and total trihalomethanes (TTHM) come from EPA’s file alone, which ends in 2019. Moses Coulee Water Association’s own annual report, which it must send you every year, has newer results for those and 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; Washington’s results run from March 18, 2020 to May 5, 2026; EPA’s compliance samples are from Aug. 18, 2013 to Oct. 20, 2014.

Testing your own tap

Moses Coulee Water Association’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 Washington certifies.

The 3 labs Washington certifies closest to the area Moses Coulee Water Association serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Anatek Labs, Inc - Wenatchee

    Wenatchee, WA · about 15 miles

    Certified for bacteria

    (509) 701-8362

  • Soiltest Farm Consultants, Inc. Laboratory

    Moses Lake, WA · about 38 miles

    Certified for nitrate, minerals and other inorganics

    (509) 765-1622

  • AV Labs, Inc

    Othello, WA · about 54 miles

    Certified for bacteria

    (509) 488-2468

All 84 certified labs for Washington

Sources

PWSID WA5305914. Rebuilt from EPA data on Oct. 18, 2026.

Also in Douglas County

All Washington utilities

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