The Water Map

Ohio

Ohio drinking water quality

Every public water system in Ohio we've verified. Each report covers one calendar year and shows the utility's own measured contaminant levels against federal limits.

Want the national picture? See where Ohio lands in our ranking of the states with the most open health-based water violations, pulled from the EPA's own records for every U.S. public water system.

1,683 water systems mapped in Ohio · showing the 800 with the most contaminant flags — explore them all on the map

Browse all 1,683 systems A–Z:12345