California Water Service-S San Francisco, CA Water Quality
California Water Service-S San Francisco: EPA violation history, explained
California Water Service-S San Francisco has a health-based violation on record, but none in the last five years - an older issue, not necessarily a current one. Population served: 64,146, over 16,449 connections.
California Water Service-S San Francisco's record against the rest of the country
4 total violations and 2 health-based ones put California Water Service-S San Francisco at the 46th percentile nationally for violation burden, rank 6,916 of 12,903.
How California Water Service-S San Francisco compares within CA
CA's 804 covered systems average 5.8 health-based violations each; California Water Service-S San Francisco carries 2, not more than typical for the state. The filter guide explains what a violation like this actually calls for.
Most recent violation on record
The last violation EPA has on record for California Water Service-S San Francisco is from 2013-01-06 (health-based: 1993-01-06). Last reported to EPA: 06/22/2026.
What kind of problem, specifically
California Water Service-S San Francisco's flagged contaminants and rule violations, grouped by what they actually mean for a filter choice rather than left as EPA's raw code list:
- Microbial contamination / treatment technique - flagged from: Coliform (TCR); Surface Water Treatment Rule
The most severe category on record is microbial contamination / treatment technique, which points toward a microbial-class filter if you want to address it directly.
What this data is and is not
Everything on this page is California Water Service-S San Francisco's own reported record under the Safe Drinking Water Act - a regulatory filing, not a sample of your tap. Water quality can still change between the meter and the faucet - household plumbing sits outside what a record of 4 logged violations can see. The guide to what this data misses covers that gap.