Johnson County Water Quality

Johnson County, Illinois has a water quality grade of F with a score of 15.8/100, based on EPA Safe Drinking Water Information System data. The county has 15 health-based drinking water violations on record.

Johnson County has 15 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.

Johnson County's water quality score of 15.8/100 is lower than the Illinois state average of 47.8. The average water quality grade across Illinois is D, based on data from 102 counties with available water quality data.

Based on EPA data, Johnson County has a water quality grade of F (15.8/100). 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).

Johnson County has 15 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.

Johnson County ranks #96 out of 102 counties in Illinois by water quality score (1 = best). With a score of 15.8/100, 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.