Pennsylvania Well Water Testing and Programs

Quick answer

About 2,202,000 people in Pennsylvania (17.3% of residents) got their water from private wells in 2010, according to USGS estimates. Pennsylvania Department of Environmental Protection runs the state’s private well guidance. The PA Department of Health's Environmental Health Capacity program partners with Penn State Extension's Drinking Water Program to offer free water testing for private well owners (the page gives no eligibility details or dates).

People on private wells: 2,202,453
Share of residents: 17.3%
Rank among states: 2nd
Well users modeled above 10 µg/L arsenic: 4.6%

Where to get your well tested in Pennsylvania

Pennsylvania Department of Environmental Protection: Private Wells, the state’s guidance for private well owners.
Well water testing in Pennsylvania: what to test for and how to collect a sample.
Certified laboratories in Pennsylvania. Use a lab certified for drinking water, so results are reliable.

Free or low-cost testing

The PA Department of Health's Environmental Health Capacity program partners with Penn State Extension's Drinking Water Program to offer free water testing for private well owners (the page gives no eligibility details or dates). (source)

Mail-in lab kits are another option when no local lab is convenient. See well water test kits for what home kits can and can’t tell you.

What to test for

Every year: total coliform bacteria and nitrate.
Before buying equipment: pH, hardness, iron, manganese and, if there’s a smell, hydrogen sulfide.
Based on location: arsenic, uranium and radon, PFAS, and lead in older plumbing.

Private wells by county

Estimated people relying on private wells in each Pennsylvania county in 2010, the share of residents that represents, and the modeled share of well users with arsenic above 10 µg/L. These are USGS model estimates (2010 population), not measurements of any well. Arsenic is hidden for counties with fewer than 500 well users.

County	People on wells	Share	Arsenic >10 µg/L
Lancaster County	130,379	25.1%	2.3%
Chester County	112,224	22.5%	3.2%
Bucks County	104,412	16.7%	7.9%
York County	94,759	21.8%	3.3%
Berks County	90,992	22.1%	4.9%
Montgomery County	69,636	8.7%	10.1%
Butler County	61,509	33.5%	3.3%
Erie County	59,007	21.0%	12.2%
Luzerne County	54,092	16.9%	4.8%
Westmoreland County	52,514	14.4%	1.9%
Crawford County	52,215	58.8%	7.5%
Dauphin County	52,136	19.4%	5.1%

Show all 67 counties

Monroe County	49,286	29.0%	2.5%
Cumberland County	48,520	20.6%	1.9%
Mercer County	45,054	38.6%	15.7%
Lehigh County	39,611	11.3%	3.9%
Lycoming County	37,508	32.3%	2.8%
Northampton County	37,035	12.4%	2.7%
Schuylkill County	36,581	24.7%	4.5%
Adams County	35,961	35.5%	4.5%
Bradford County	35,191	56.2%	6.7%
Franklin County	34,854	23.3%	2.2%
Beaver County	33,955	19.9%	3.2%
Washington County	33,396	16.1%	2.5%
Indiana County	32,921	37.0%	1.9%
Wayne County	30,766	58.2%	6.3%
Lawrence County	30,249	33.2%	5.8%
Blair County	30,182	23.7%	2.0%
Lebanon County	29,869	22.4%	2.5%
Bedford County	29,450	59.2%	2.8%
Perry County	28,647	62.3%	4.8%
Lackawanna County	27,251	12.7%	4.9%
Susquehanna County	27,075	62.4%	6.5%
Columbia County	26,338	39.1%	4.4%
Allegheny County	26,145	2.1%	2.5%
Somerset County	26,016	33.5%	2.0%
Armstrong County	25,082	36.4%	2.0%
Northumberland County	24,113	25.5%	5.9%
Huntingdon County	22,567	49.2%	5.9%
Tioga County	22,315	53.2%	6.1%
Pike County	22,132	38.6%	2.4%
Carbon County	21,357	32.7%	4.2%
Centre County	20,500	13.3%	1.4%
Venango County	20,128	36.6%	2.4%
Cambria County	19,640	13.7%	1.7%
Warren County	19,531	46.7%	3.6%
Union County	19,488	43.4%	7.1%
Wyoming County	18,243	64.5%	6.6%
Fayette County	17,966	13.2%	1.9%
Snyder County	17,521	44.1%	5.4%
Mifflin County	16,722	35.8%	5.1%
Jefferson County	16,202	35.8%	1.7%
Delaware County	15,295	2.7%	2.3%
Juniata County	15,289	62.1%	5.7%
Clearfield County	14,994	18.4%	2.0%
Clarion County	13,903	34.8%	1.3%
McKean County	12,787	29.4%	4.0%
Fulton County	10,846	73.1%	5.0%
Montour County	8,987	49.2%	5.6%
Greene County	8,741	22.6%	2.1%
Potter County	7,405	42.4%	6.0%
Clinton County	6,940	17.7%	2.4%
Elk County	5,066	15.9%	1.8%
Sullivan County	4,804	74.7%	3.0%
Forest County	3,845	49.8%	1.8%
Philadelphia County	3,041	0.2%	4.6%
Cameron County	1,267	24.9%	3.0%

Counties with the highest modeled arsenic share: Mercer County (15.7%), Erie County (12.2%), Montgomery County (10.1%), Bucks County (7.9%), Crawford County (7.5%).

After you get results

Enter your numbers in the test results tool to see what needs treating and in what order. The guide to reading a well water test explains units and limits.

Common questions

Does Pennsylvania offer free well water testing?

Who oversees private wells in Pennsylvania?

Pennsylvania Department of Environmental Protection (Private Wells) publishes guidance for private well owners. Private wells aren’t covered by the federal Safe Drinking Water Act, so testing and treatment are up to the owner.

How many people use private wells in Pennsylvania?

USGS estimates about 2,202,000 people, or 17.3% of the population in 2010. That ranks 2nd of the states covered by the estimate.

What should I test my well for in Pennsylvania?

Test every year for total coliform bacteria and nitrate, plus pH, hardness, iron and manganese before buying equipment. Ask the state program or a certified lab about local concerns such as arsenic, uranium or PFAS.