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Gross Alpha in Private Wells

Summary Indicator Report Data View Options

Gross Alpha in Private Wells by County, New Jersey, 2002-2022

Why Is This Important?

Gross Alpha is a test that is performed to measure the overall radioactivity in drinking water. Naturally occurring radioactive elements emit alpha particles as they decay. Alpha radiation exists in soil, air, and water. Sampling of public and private wells that draw water from southern New Jersey's Cohansey aquifer has shown elevated levels of naturally occurring radioactivity. Exposure to radium over a long period of time is believed to increase one's lifetime risk of developing certain types of cancer.


Percent of tested private wells with gross alpha exceeding the maximum contaminant level of 15 picoCuries per liter (pCi/l)

Data Source

Private Well Testing Act Data, Division of Water Supply and Geoscience, New Jersey Department of Environmental Protection

How the Measure is Calculated

Numerator:Number of tested private wells with gross alpha concentration exceeding the maximum contaminant level of 15 pCi/l in a specified period of time
Denominator:Number of tested private wells in a specified period of time

How Are We Doing?

Between September 2002 and December 2022, 10.8% of 91,798 private wells in New Jersey tested for gross alpha exceeded the MCL of 15 pCi/l. Gross alpha exceedances were most commonly found in Camden, Cumberland, Gloucester, Middlesex, and Salem Counties. Online maps showing gross alpha exceedances are available at the county level, municipal level, and for 2 mile by 2 mile grids from NJDEP, [].

What Is Being Done?

The New Jersey Private Well Testing Act (N.J.S.A. 58:12A-26 et seq.) became effective in September 2002. The PWTA requires the buyer or the seller of a property to test untreated well water prior to the sale and review the results prior the closing of title. It also requires landlords to test the private well water supplied to their tenants every five years and provide their tenants with a written copy of the results. The data generated by this program are provided to the homeowners by the laboratory performing the analyses and then sent to the New Jersey Department of Environmental Protection (NJDEP). The NJDEP notifies local health agencies when a well within their jurisdiction is tested under the PWTA. The data from the PWTA are used by NJDEP to assess the quality of the water from private wells throughout the state.

Available Services

If your drinking water comes from a private well, you are responsible for testing. The NJDEP recommends that you use a laboratory that is NJDEP-certified. You can call the NJDEP Office of Quality Assurance at (609) 292-3950 for information on laboratories certified to test drinking water or look for the information online at: [] using the "Search by Category" option, select "Certified Laboratories", and search for "Certified Drinking Water Labs", "PWTA Laboratories Certified for Sampling", or "Laboratories Certified by Parameter". Testing is required for sale of residential real estate when a private well is the source of drinking water. For more information, contact the NJDEP Private Well Testing Program at (866) 479-8378 or visit: [] Private Well Testing Act Frequently Asked Questions: [] NJ Private Well Testing Act Data Summary, by county, municipality, and 2 mile by 2 mile grid: [] NJDOH Drinking Water Facts: Private Wells, [] NJDOH Drinking Water and Public Health Project, [] To inquire about New Jersey well permitting and regulation, contact the NJDEP Division of Water Supply at (609) 984-6831. For information on federal drinking water regulations, and other water safety issues, contact the United States Environmental Protection Agency Safe Drinking Water Hotline at (800) 426-4791.

Indicator Data Last Updated On 05/11/2023, Published on 05/11/2023
Environmental Public Health Tracking Project, New Jersey Department of Health, PO Box 369, Trenton, NJ 08625-0369, e-mail: (