Butler County, Ohio: drinking water report. Butler County sits north of Cincinnati with about 390,000 residents, including Hamilton and Middletown.
Butler County sits north of Cincinnati with about 390,000 residents, including Hamilton and Middletown. The Great Miami River and its buried valley aquifer – the same system that serves Dayton – provide most of the county's water. Butler County Water and Sewer Department and municipal systems in Hamilton and Middletown draw from both surface and groundwater sources. Paper mills and steel manufacturing defined Middletown's economy for most of the 20th century.
The Great Miami Buried Valley Aquifer's vulnerability shows up in Butler County as it does upstream in Montgomery County. According to the Ohio EPA's 2024 source water assessment, the aquifer in Butler County shows detections of atrazine from agricultural application and TCE from industrial sources at several monitoring points. Concentrations remain below MCLs in public supply wells but indicate ongoing contamination pathways.
AK Steel's Middletown Works (now Cleveland-Cliffs) operated coke ovens and steel processing for decades, contributing PAHs and heavy metals to local groundwater. The EPA's UCMR5 data also detected PFAS in Butler County water systems. A 2024 Ohio EPA study found PFAS in the Great Miami River at concentrations between 5-12 ppt at multiple sampling locations.
Butler County's position on the Great Miami Aquifer means your water comes from a productive but exposed source. The aquifer recharges quickly, which keeps it flowing but also allows surface contaminants to reach it relatively fast.
Check your water to see current results for your address. For the mix of agricultural and industrial compounds found in this area, reverse osmosis provides the most comprehensive household protection. Our water filter guide covers systems appropriate for aquifer-sourced water. Get your detailed report for trend data, and visit our Ohio page for statewide context.