York County, Pennsylvania: drinking water report. York County sits in south-central Pennsylvania, home to about 460,000 residents.
York County sits in south-central Pennsylvania, home to about 460,000 residents. The York Water Company – the oldest investor-owned water utility in the country, founded in 1816 – serves much of the county from Lake Williams and Lake Redman. Other communities rely on groundwater from the Piedmont and Blue Ridge geological formations.
York County's reservoir-based supply provides generally clean surface water. UCMR5 data shows low-level PFAS detections in county systems, without the military point sources that affect neighboring counties like Cumberland (home to the former New Cumberland Army Depot).
The county's mix of agricultural and suburban land use means nitrate from farming operations affects some groundwater systems in the western and southern parts of the county. According to the Pennsylvania DEP, two community water systems in York County reported nitrate levels above 50% of the MCL during the most recent monitoring period – not in violation, but trending in the wrong direction.
York County benefits from a strong surface water supply through the York Water Company. Groundwater-dependent communities should monitor nitrate and PFAS trends.
Check your water for data specific to your provider. For nitrate concerns, reverse osmosis is the most effective household treatment. Our water filter guide covers certified systems. Pull your detailed report, and visit our Pennsylvania page for statewide data.
Drinking water is one exposure route. These federal datasets also cover York County, PA.
The EPA places York 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.
56% of homes in York 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 York County, PA averages 8.5 µg/m³, within 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
14 public water systems serving York County, PA have EPA lead testing on record. The reported lead sample skews toward systems that already flagged a problem, so its exceedance rate is not directly comparable with other areas. 7 water systems serving York County, PA carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Total Organic Carbon | 3 |
| Ground Water Rule | 2 |
| Haloacetic Acids (HAA5) | 1 |
| Surface Water Treatment Rule | 1 |
| Total Trihalomethanes (TTHM) | 1 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.