Skip directly to searchSkip directly to the site navigationSkip directly to the page's main content

Complete Health Indicator Report of Gross Alpha in Private Wells


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


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


Number of tested private wells in a specified period of time

Data Interpretation Issues

Gross alpha particle activity is a surrogate measurement for radium and is a measurement of all alpha radioactivity present, regardless of the specific radionuclide source. The federal maximum contaminant level (MCL) for gross alpha is 15 pCi/l minus the contribution from uranium. Initially, nine southern New Jersey counties in the Coastal Plain (Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Monmouth, Ocean, and Salem) and three northern counties (Hunterdon, Mercer, and Middlesex) were required to monitor for gross alpha. In the Coastal Plain, where the only radionuclide present is radium, this surrogate test works well. However, outside of the Coastal Plain, groundwater samples may contain uranium, radium, or a combination of both. Both elements emit alpha radioactivity and so gross alpha measurements do not provide sufficient information to determine whether a particular sample exceeds the drinking water MCL. Currently, testing for gross alpha is required in all 21 NJ counties. Of all of the private wells sampled statewide, 10.9 percent contained gross alpha levels above the federal MCL.

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.

How Are We Doing?

Between September 2002 and December 2018, 10.9% of 64,846 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 (35.6% of wells), Cumberland (29.9% of wells), Salem (17.2% of wells), and Sussex (15.1% of wells) 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.

Related Indicators

Related Risk Factors Indicators:

Data Tables

Gross Alpha in Private Wells, Percent of Tested Wells Exceeding MCL, by County, September 2002 through December 2018

CountyPercent of Wells Exceeding MCLNumer- atorDenom- inator
Record Count: 22
Cape May0.9505,319
New Jersey10.97,05964,846

Data Notes

**Results by county are suppressed when the number of tested wells was less than 10. Denominator is the number of tested private wells. Data Source: NJ Department of Environmental Protection, Division of Water Supply and Geoscience, and Division of Science, Research, and Environmental Health, obtained on March 2, 2020.

Page Content Updated On 03/03/2020, Published on 03/03/2020
The information provided above is from the Department of Health's NJSHAD web site ( The information published on this website may be reproduced without permission. Please use the following citation: " Retrieved Thu, 23 May 2024 1:57:39 from Department of Health, New Jersey State Health Assessment Data Web site: ".

Content updated: no date