Ponderosa Basin Mutual Wtr Co

Water Quality Snapshot: Ponderosa Basin Mutual Wtr Co

Ponderosa Basin Mutual Wtr Co is a private-owned community water system that delivers drinking water to 798 residents in Mariposa, California (Mariposa County) through 317 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 30 total violations for this system , of which 16 (53%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 12 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 16 violations (MCL, health-based). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

Across California, EPA tracks 7,249 public water systems serving 42,404,883 people, with 153,308 cumulative violations and 63,983 health-based violations on record. About 89% of systems in the state carry at least one violation, and state-wide the average per system is 21.1 violations. Statewide, 447 of 694 UCMR5-tested systems have reported PFAS detections (64.4%).

Ponderosa Basin Mutual Wtr Co's 30 violations sit above the California average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.