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Patterson Addition

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
22 people
Connections
20
Water source
Groundwater
Based in
Spokane, WA
County
Spokane
Owner
Private
The ZIP code it serves

99224

The short answer

Nothing in EPA’s and Washington’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Nitrate: Washington’s own results, samples taken from July 8, 2020 to Dec. 22, 2025, with EPA’s 2012 to 2019 file for earlier years.

Arsenic, chromium (total) and fluoride: EPA’s compliance monitoring file, samples taken from Nov. 1, 2017 to Nov. 1, 2017. Newer results are in the utility’s annual water quality report.

Below EPA’s limits1

Nitrate

Comes from the source

Below EPA’s limits

5.8ppm

Highest sample; found in 7 of 7

2025 average: 5.3 ppm

The highest sample, in 2025, was 5.8 ppm, below EPA’s legal limit of 10 ppm. That was also the latest year on file, and its two samples averaged 5.3 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 5.1 ppm, in 2017.

What handles it

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

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. Nitrate results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Arsenic, chromium (total) and fluoride come from EPA’s file alone, which ends in 2019. Patterson Addition’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 July 8, 2020 to Dec. 22, 2025; EPA’s compliance samples are from Nov. 1, 2017 to Nov. 1, 2017.

Testing your own tap

Patterson Addition’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 Patterson Addition serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Anatek Labs, Inc - Spokane

    Spokane, WA · about 7 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity

    (509) 838-3999

  • Tshimakain Creek Laboratories

    Spokane Valley, WA · about 11 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (509) 928-3577

  • Eurofins Spokane

    Spokane Valley, WA · about 13 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (509) 924-9200

All 84 certified labs for Washington

Sources

PWSID WA5366565. Rebuilt from EPA data on Oct. 18, 2026.

Also in Spokane County

All Washington utilities

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