Is Prosser, WA tap water safe?
The short answer
None of the 4 utilities serving Prosser has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Washington’s records.
City of Prosser, which serves the most people here, has 1 result above EPA’s health benchmark. The worst: Lithium at 27.7 ppb, above EPA’s health benchmark. A health benchmark is a level EPA screens with, not a legal limit.
The water from City of Prosser is soft, typically 51 mg/L (3 grains per gallon). How Washington’s water compares.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Prosser’s ZIP codes, from EPA’s estimates.
- Open report
City of Prosser
Washington · serves 8,030 people · under 100 in Prosser
1 result above EPA’s health benchmark. The worst: Lithium at 27.7 ppb, above EPA’s health benchmark. Hardness: soft, typically 51 mg/L (3 grains per gallon).
No health-based violations since 2016
- Open report
Alderdale Water Assn
Washington · serves 171 people · based in Prosser
Nothing in its records is above a health goal.
No health-based violations since 2016
- Open report
Rainbow Court
Washington · serves 120 people · based in Prosser
1 result above the health goal. The worst: Arsenic at 5.2 ppb, above the health goal. Hardness: soft, 40 mg/L (2.3 grains per gallon).
No health-based violations since 2016
- Open report
Roza Heights Water Assn
Washington · serves 110 people · based in Prosser
1 result above the health goal. The worst: Arsenic at 2.7 ppb, above the health goal. Hardness: very hard, 299 mg/L (17.5 grains per gallon).
No health-based violations since 2016
Water testing near Prosser
The 3 labs Washington certifies closest to Prosser, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Energy NW Environmental (PPL) Lab
Richland, WA · about 20 miles
Certified for bacteria
Energy Northwest Environmental Services Lab
Richland, WA · about 22 miles
Certified for nitrate, lead and copper, metals, minerals and other inorganics
Ag Health Laboratories, Inc.
Sunnyside, WA · about 22 miles
Certified for bacteria, nitrate
ZIP codes in Prosser
Which ZIP codes are in Prosser: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: Washington State Department of Ecology, Lab Accreditation Program, environmental laboratories accredited for drinking water analyses; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Prosser
Other towns in Benton County with a page of their own.
What to do next
- Read City of Prosser’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water