Lancaster County, Pennsylvania: drinking water report. Lancaster County sits in the heart of Pennsylvania Dutch Country, home to about 560,000 residents.
Lancaster County sits in the heart of Pennsylvania Dutch Country, home to about 560,000 residents. Water comes from the Conestoga River and Susquehanna River for surface systems, and from limestone aquifers for the many small groundwater systems that serve rural and suburban communities. The county's intense agricultural activity – Lancaster is one of the most productive non-irrigated agricultural counties in the United States – directly impacts water quality.
Nitrate contamination from agricultural fertilizer and manure application is the defining water quality challenge in Lancaster County. The county sits on karst limestone, which means surface contamination reaches groundwater rapidly through sinkholes and dissolved rock channels. According to the USGS, approximately 20% of domestic wells tested in Lancaster County exceeded the nitrate MCL of 10 mg/L.
UCMR5 data shows PFAS detections in several county water systems, but nitrate from agriculture is the more widespread concern. The Lancaster County Conservation District has documented nitrogen loading rates that are among the highest in the Chesapeake Bay watershed.
If you are on a private well in Lancaster County, nitrate testing is especially important – private wells are not subject to federal monitoring requirements.
Check your water for data specific to your area. For nitrate, reverse osmosis is the most effective household treatment. Our water filter guide covers which systems are certified for nitrate removal. Pull your detailed report, and visit our Pennsylvania page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Lancaster County, PA.
The EPA places Lancaster County, PA in Zone 1 - the EPA's highest-risk category, where the predicted average indoor radon level is above 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
54% of homes in Lancaster County, PA were built before 1980, and 24% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Lancaster County, PA averages 9.4 µg/m³, above the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide