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Doc Stewart

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
100 people
Connections
3
Water source
Groundwater
Based in
Yakima, WA
County
Grant
Owner
Private
Hardness
Moderately hard

The short answer

1 result is above the health goal. The worst: Uranium, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Uranium, nitrate, fluoride, arsenic and chromium (total): Washington’s own results, samples taken from Jan. 14, 2020 to April 3, 2024, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal1

Uranium

Comes from the source

Above the health goal

3.4ppb

Highest yearly average, 2023 to 2024

Averaged by year, the highest was 3.4 ppb, in 2024: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That was also the latest year on file.

What handles it

Below EPA’s limits2

Nitrate

Comes from the source

Below EPA’s limits

8.0ppm

Highest sample; found in 11 of 11

2024, one sample: 1.8 ppm

The highest sample, in 2020, was 8.0 ppm, below EPA’s legal limit of 10 ppm. In 2024, the latest year on file, its one sample was 1.8 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 4.7 ppm, in 2018.

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

0.3ppm

Highest yearly average, 2024

Averaged by year, the highest was 0.3 ppm, in 2024, below EPA’s legal limit of 4.0 ppm. That is the only year on file.

What handles it

3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • 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.”

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

None of the filters TapBuff has checked so far carry these claims. Search the certifier listings for the claim above.

Compare five-year costs

Hardness

Moderately hard, 120 mg/L (7 grains per gallon), at its one sampling point, in 2024.

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 7 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 23 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Uranium, nitrate, fluoride, arsenic and chromium (total) results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Doc Stewart’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; Washington’s results run from Jan. 14, 2020 to April 3, 2024.

Testing your own tap

Doc Stewart’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.

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

All 84 certified labs for Washington

Sources

PWSID WA53AD731. Rebuilt from EPA data on Oct. 18, 2026.

Also in Grant County

All Washington utilities

What to do next