Mariposa County Water Quality

Mariposa County, California has a water quality grade of F with a score of 25.0/100, based on EPA Safe Drinking Water Information System data. The county has 6 health-based drinking water violations on record.

Mariposa County has 6 health-based drinking water violations recorded by the EPA. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.

Mariposa County's water quality score of 25.0/100 is lower than the California state average of 44.6. The average water quality grade across California is D, based on data from 58 counties with available water quality data.

Based on EPA data, Mariposa County has a water quality grade of F (25.0/100). This indicates below-average water quality with significant compliance issues. Residents may want to consider home water filtration. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).

Mariposa County has 6 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.

Mariposa County ranks #51 out of 58 counties in California by water quality score (1 = best). With a score of 25.0/100, it falls in the bottom third of counties statewide. Rankings are based on EPA Safe Drinking Water Information System (SDWIS) data including health-based violations and compliance records.