Seattle, WA Tap Water Quality

Tap water in Seattle, WA ranks among the best in the state, maintaining a remarkable average water quality score of 95/100 across its 62 ZIP codes. Based on recent EPA Safe Drinking Water Act compliance records, water provided by Seattle Public Utilities and other municipal suppliers has consistently met or exceeded federal safety standards. This top-tier "A" grade reflects strong infrastructure, diligent monitoring by Washington State Department of Health, and low contaminant levels.

A major factor in Seattle's high rating is its flawless health-based violation record. Over the past 5 years of EPA tracking, local water systems have recorded zero health-based violations. This means that regulated contaminants—such as lead, arsenic, and harmful bacteria—have not exceeded the Maximum Contaminant Levels (MCLs) allowed by federal law. Drawing primarily from surface water, the city utilizes advanced filtration to maintain this standard.

Additionally, lead exposure risk remains a critical issue for certain neighborhoods. EPA data indicates that 28 out of 62 ZIP codes in Seattle are rated as High or Very High risk for lead. This risk is often driven by aging homes with pre-1986 plumbing containing lead solder or service lines. Families in these areas should test their tap water and consider NSF/ANSI 53 certified filters.