WA / Prosser
WA · Tap water records
Prosser tap water, in plain English
Here is what the EPA's own data shows about tap water in Prosser. According to EPA SDWIS data retrieved June 2026, Prosser is served by 5 active community water systems, together reported to serve about 6,736 people.
As of June 2026, EPA records show 50 violations across the community water system(s) serving Prosser, going back to the earliest EPA record. 7 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Prosser City Of
6,211 served · groundwater · PWSID WA5369750 - Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2023. All have since returned to compliance, per EPA records.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2014. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between January 2010 and January 2014. All have since returned to compliance, per EPA records.
Alderdale Water Assn
171 served · groundwater · PWSID WA5326214 - Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 11 times between July 2012 and July 2024. All have since returned to compliance, per EPA records.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between July 2017 and May 2021. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between January 2006 and January 2021. All have since returned to compliance, per EPA records.
- Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between January 2020 and January 2021. All have since returned to compliance, per EPA records.
Kiona Village Court
124 served · groundwater · PWSID WA5342175 As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.
Rainbow Court
120 served · groundwater · PWSID WA5370770 - Health-based Nitrate: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 7 times between January 2003 and April 2004. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2016 and July 2023. All have since returned to compliance, per EPA records.
Roza Heights Water Assn
110 served · groundwater · PWSID WA5374800 - Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2023. EPA records do not show all of these as returned to compliance.
- Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2023. EPA records do not show all of these as returned to compliance.
- Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2018. All have since returned to compliance, per EPA records.
- Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between January 2000 and January 2013. All have since returned to compliance, per EPA records.
- Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2012. All have since returned to compliance, per EPA records.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.