New Jersey Well Water Testing and Programs

Quick answer

About 766,000 people in New Jersey (8.7% of residents) got their water from private wells in 2010, according to USGS estimates. New Jersey Department of Environmental Protection runs the state’s private well guidance. The NJ Department of Health's Private Well Outreach Project offers free testing for radioactivity, iron and manganese to private well owners in eligible South Jersey municipalities (limited, first-come first-served, subject to available funding).

People on private wells: 766,059
Share of residents: 8.7%
Rank among states: 17th
Well users modeled above 10 µg/L arsenic: 3.2%

Where to get your well tested in New Jersey

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

Free or low-cost testing

The NJ Department of Health's Private Well Outreach Project offers free testing for radioactivity, iron and manganese to private well owners in eligible South Jersey municipalities (limited, first-come first-served, subject to available funding). (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 New Jersey 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
Ocean County	70,423	12.2%	2.7%
Morris County	66,137	13.4%	2.8%
Sussex County	65,428	43.8%	2.0%
Atlantic County	60,817	22.2%	2.8%
Burlington County	60,249	13.4%	2.4%
Hunterdon County	58,793	45.8%	6.9%
Somerset County	49,094	15.2%	8.2%
Cumberland County	41,558	26.5%	1.8%
Monmouth County	39,128	6.2%	1.5%
Gloucester County	36,037	12.5%	2.1%
Cape May County	32,932	33.9%	2.9%
Warren County	32,355	29.8%	2.2%

Show all 21 counties

Passaic County	26,882	5.4%	1.9%
Mercer County	24,688	6.7%	4.3%
Bergen County	24,536	2.7%	2.5%
Salem County	24,496	37.1%	2.2%
Camden County	23,921	4.7%	2.5%
Middlesex County	20,430	2.5%	3.3%
Essex County	5,044	0.6%	2.6%
Union County	2,658	0.5%	1.9%
Hudson County	453	0.1%	–

Counties with the highest modeled arsenic share: Somerset County (8.2%), Hunterdon County (6.9%), Mercer County (4.3%), Middlesex County (3.3%), Cape May County (2.9%).

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 New Jersey offer free well water testing?

Who oversees private wells in New Jersey?

New Jersey 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 New Jersey?

USGS estimates about 766,000 people, or 8.7% of the population in 2010. That ranks 17th of the states covered by the estimate.

What should I test my well for in New Jersey?

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.