Washington County, Pennsylvania: drinking water report. Washington County in southwestern Pennsylvania has about 208,000 residents.
Washington County in southwestern Pennsylvania has about 208,000 residents. The county draws water from surface sources including Ten Mile Creek and the Monongahela River, with Pennsylvania American Water and several municipal authorities providing service. The county sits atop the Marcellus Shale formation, making it one of the most active natural gas drilling regions in the eastern United States. That drilling activity adds a modern contamination concern to the area's existing coal mining legacy.
Fracking operations in Washington County have generated community concerns about groundwater contamination. According to the Pennsylvania DEP's 2024 oil and gas compliance report, the county had over 1,800 active unconventional gas wells. While the DEP maintains that properly constructed wells do not contaminate aquifers, the department investigated 12 water supply complaints related to drilling activity in Washington County during 2024.
Coal mine drainage remains a concurrent issue. A 2024 DEP assessment documented 90 miles of impaired streams in the county from abandoned mine drainage. The EPA's UCMR5 data also showed PFAS detections in Washington County's public water systems, likely from multiple diffuse sources rather than a single military or industrial origin.
Washington County's dual legacy of coal mining and modern gas drilling means groundwater quality depends heavily on location. Private well owners near active drilling pads should establish a baseline water quality test before drilling begins and retest periodically.
Check your water for the latest data on your supply. For the range of contaminants possible in this area – from methane and VOCs to mine drainage metals – reverse osmosis provides the broadest household protection. Our water filter guide covers both mining and drilling-related contamination scenarios. Get your detailed report for trend data, and visit our Pennsylvania page for statewide patterns.