Skip to content
TapBuff
ZIP

Alderdale Water Assn

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
171 people
Connections
57
Water source
Groundwater
Based in
Prosser, WA
County
Klickitat
Owner
Private

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 Aug. 30, 2022 to Oct. 2, 2024, with EPA’s 2012 to 2019 file for earlier years.

Fluoride, arsenic and chromium (total): EPA’s compliance monitoring file, samples taken from Dec. 11, 2013 to Sept. 29, 2017. Newer results are in the utility’s annual water quality report.

Below EPA’s limits1

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.49ppm

Highest yearly average, 2013 to 2017

2017, one sample: 0.38 ppm

Averaged by year, the highest was 0.49 ppm, in 2016, below EPA’s legal limit of 4.0 ppm. In 2017, the latest year on file, its one sample was 0.38 ppm.

What handles it

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

Violations since 2016

No health-based violations on file with EPA since 2016. There are 10 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 2022 on, with EPA’s national file for 2012 to 2019. Fluoride, arsenic and chromium (total) come from EPA’s file alone, which ends in 2019. Alderdale Water Assn’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 Aug. 30, 2022 to Oct. 2, 2024; EPA’s compliance samples are from Dec. 11, 2013 to Sept. 29, 2017.

Testing your own tap

Alderdale Water Assn’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 Alderdale Water Assn 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 WA5326214. Rebuilt from EPA data on Oct. 18, 2026.

Also in Klickitat County

All Washington utilities

What to do next