Washington Tap Water Quality Report

Drinking water quality in Washington is widely considered to be above the national average, maintaining an impressive composite safety score of 77.9/100 across its 726 monitored ZIP codes. Based on the latest records from the EPA's Safe Drinking Water Information System (SDWIS), a remarkable 40% of ZIP codes in Washington have earned an "A" grade. This reflects strong regulatory compliance, robust municipal water treatment infrastructure, and generally low levels of detected health-based contaminants across most communities in the state.

Over the past 5 years, water utilities in Washington have recorded a total of 1,630 violations, of which 121 were strictly health-based. While administrative and reporting violations are common nationwide, health-based violations mean that certain contaminants exceeded the EPA's Maximum Contaminant Levels (MCLs) at some point. Washington State Department of Health, which acts as the primary regulatory authority in the state, typically works closely with these utilities to issue boil water advisories or mandate infrastructure upgrades when these limits are breached.

One of the most pressing concerns for Washington residents is the elevated risk of lead exposure. EPA models and historical monitoring indicate that 36.6% of ZIP codes in Washington are classified as High or Very High risk for lead. This is frequently associated with older housing stock built before the 1986 federal ban on lead pipes and solder. Residents living in older homes should strongly consider having their tap water independently tested and utilizing a certified NSF/ANSI 53 water filter for drinking and cooking.