Private Well Water Testing in Pennsylvania
County-by-county USGS area-risk estimates for private wells across Pennsylvania — arsenic exceedance probability and private-well population — plus how to test your own well at a Pennsylvania-certified laboratory.
Pennsylvania private-well risk summary
Counties covered
67
Pennsylvania counties with modeled risk data.
People on private wells
area estimate2,202,134
estimated across covered Pennsylvania counties.
Average arsenic risk
area estimate4%
average modeled chance a well exceeds 10 µg/L arsenic across covered counties.
Pennsylvania counties
- Lancaster County2% arsenic exceedance (area estimate)130,417 people on private wells
- Chester County3% arsenic exceedance (area estimate)112,061 people on private wells
- Bucks County8% arsenic exceedance (area estimate)104,968 people on private wells
- York County3% arsenic exceedance (area estimate)94,819 people on private wells
- Berks County4% arsenic exceedance (area estimate)90,806 people on private wells
- Montgomery County9% arsenic exceedance (area estimate)69,501 people on private wells
- Butler County3% arsenic exceedance (area estimate)61,561 people on private wells
- Erie County9% arsenic exceedance (area estimate)59,641 people on private wells
- Luzerne County4% arsenic exceedance (area estimate)54,168 people on private wells
- Westmoreland County2% arsenic exceedance (area estimate)52,730 people on private wells
- Crawford County8% arsenic exceedance (area estimate)52,212 people on private wells
- Dauphin County6% arsenic exceedance (area estimate)51,955 people on private wells
- Monroe County3% arsenic exceedance (area estimate)49,459 people on private wells
- Cumberland County2% arsenic exceedance (area estimate)48,610 people on private wells
- Mercer County16% arsenic exceedance (area estimate)45,069 people on private wells
- Lehigh County3% arsenic exceedance (area estimate)39,473 people on private wells
- Lycoming County3% arsenic exceedance (area estimate)37,554 people on private wells
- Northampton County3% arsenic exceedance (area estimate)36,938 people on private wells
- Schuylkill County5% arsenic exceedance (area estimate)36,638 people on private wells
- Adams County4% arsenic exceedance (area estimate)35,945 people on private wells
- Bradford County6% arsenic exceedance (area estimate)35,079 people on private wells
- Franklin County2% arsenic exceedance (area estimate)34,829 people on private wells
- Beaver County3% arsenic exceedance (area estimate)33,971 people on private wells
- Washington County2% arsenic exceedance (area estimate)33,446 people on private wells
- Indiana County2% arsenic exceedance (area estimate)32,885 people on private wells
- Wayne County6% arsenic exceedance (area estimate)30,920 people on private wells
- Lawrence County6% arsenic exceedance (area estimate)30,219 people on private wells
- Blair County2% arsenic exceedance (area estimate)30,106 people on private wells
- Lebanon County3% arsenic exceedance (area estimate)29,904 people on private wells
- Bedford County3% arsenic exceedance (area estimate)29,365 people on private wells
- Perry County5% arsenic exceedance (area estimate)28,639 people on private wells
- Susquehanna County6% arsenic exceedance (area estimate)27,098 people on private wells
- Lackawanna County4% arsenic exceedance (area estimate)27,031 people on private wells
- Columbia County5% arsenic exceedance (area estimate)26,276 people on private wells
- Somerset County2% arsenic exceedance (area estimate)26,065 people on private wells
- Allegheny County3% arsenic exceedance (area estimate)25,927 people on private wells
- Armstrong County2% arsenic exceedance (area estimate)24,951 people on private wells
- Northumberland County6% arsenic exceedance (area estimate)23,952 people on private wells
- Huntingdon County5% arsenic exceedance (area estimate)22,686 people on private wells
- Tioga County6% arsenic exceedance (area estimate)22,200 people on private wells
- Pike County2% arsenic exceedance (area estimate)21,905 people on private wells
- Carbon County4% arsenic exceedance (area estimate)21,155 people on private wells
- Centre County2% arsenic exceedance (area estimate)20,481 people on private wells
- Venango County2% arsenic exceedance (area estimate)20,100 people on private wells
- Cambria County2% arsenic exceedance (area estimate)19,711 people on private wells
- Union County6% arsenic exceedance (area estimate)19,578 people on private wells
- Warren County3% arsenic exceedance (area estimate)19,511 people on private wells
- Wyoming County7% arsenic exceedance (area estimate)18,250 people on private wells
- Fayette County2% arsenic exceedance (area estimate)17,872 people on private wells
- Snyder County5% arsenic exceedance (area estimate)17,605 people on private wells
- Mifflin County4% arsenic exceedance (area estimate)16,686 people on private wells
- Jefferson County2% arsenic exceedance (area estimate)16,181 people on private wells
- Juniata County6% arsenic exceedance (area estimate)15,272 people on private wells
- Clearfield County2% arsenic exceedance (area estimate)15,069 people on private wells
- Delaware County3% arsenic exceedance (area estimate)15,021 people on private wells
- Clarion County1% arsenic exceedance (area estimate)13,971 people on private wells
- McKean County4% arsenic exceedance (area estimate)12,805 people on private wells
- Fulton County5% arsenic exceedance (area estimate)10,842 people on private wells
- Montour County6% arsenic exceedance (area estimate)8,951 people on private wells
- Greene County2% arsenic exceedance (area estimate)8,714 people on private wells
- Potter County6% arsenic exceedance (area estimate)7,393 people on private wells
- Clinton County3% arsenic exceedance (area estimate)6,943 people on private wells
- Elk County2% arsenic exceedance (area estimate)5,070 people on private wells
- Sullivan County3% arsenic exceedance (area estimate)4,891 people on private wells
- Forest County2% arsenic exceedance (area estimate)3,838 people on private wells
- Philadelphia County4% arsenic exceedance (area estimate)2,977 people on private wells
- Cameron County3% arsenic exceedance (area estimate)1,268 people on private wells
Find a Pennsylvania-certified testing lab
Get your well tested at a Pennsylvania-certified laboratory. We list certification programs by state.
These figures are USGS area estimates: statistical groundwater models describing how likely elevated contaminant levels are across a county. They are not designed to predict the concentration in any single well. Only testing your own well reveals its water quality.
By TapWaterData Editorial
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