San Francisco

San Francisco, CA receives a water quality score of 94/100 (Grade A) based on EPA Safe Drinking Water Information System (SDWIS) compliance data for 3 public water systems serving the area.

San Francisco's water quality is above the national average, with strong compliance records and low contaminant levels. Residents generally receive clean, safe tap water that meets EPA standards.

San Francisco's score of 94 is 4 points above the California state average of 90, and above the nationwide average of roughly 78/100 across all U.S. states.

For households and homebuyers in this large West Coast city, the water supply across San Francisco, California's multiple distribution networks maintains an exemplary rating for safety and quality. This consistently high compliance provides peace of mind, particularly when considering the broader regional context of Central Valley agriculture, varied geology, and the typical environmental demands of large urban centers. The strength of these local systems suggests robust treatment and infrastructure capable of delivering reliable tap water throughout the community.

Water quality data is sourced from the U.S. EPA SDWIS database and updated quarterly. Learn about our scoring methodology → Read our California water quality rankings report →