Definition

Percent of tested private wells with nitrate concentration exceeding the maximum contaminant level (MCL) of 10 milligrams per liter

Numerator

Number of tested private wells with nitrate concentration exceeding the maximum contaminant level of 10 milligrams per liter in a specified time period

Denominator

Number of tested private wells in a specified time period

Why Is This Important?

Nitrate is a nitrogen compound that occurs naturally in soil, water, plants, and food. It may be formed when microorganisms in the environment break down organic materials, such as plants, animal manure, and sewage. Nitrate can also be found in chemical fertilizers. Nitrate can get into drinking water from runoff of farms, golf courses and lawns, landfills, animal feedlots, and septic systems. High levels of nitrate in drinking water can lead to methemoglobinemia, a form of anemia, particularly in infants ("blue baby syndrome") and pregnant women.

How Are We Doing?

Between September 2002 and December 2018, about 2.9% of 111,011 wells tested had concentrations of nitrate above the maximum contaminant level (MCL) of 10 milligrams per liter. Two counties had much higher rates of MCL exceedance, Cumberland (14.3% of wells) and Salem (10.1% of wells). Online maps showing detection of nitrate are available at the county level, municipal level, and for 2 mile by 2 mile grids from NJDEP, [http://arcg.is/1CPkHyC].

What Is Being Done?

The New Jersey Private Well Testing Act (PWTA) became effective in September 2002. The PWTA requires the buyer or the seller of real property to test the well water prior to sale and review the results prior to closing of title. It also requires landlords to test the private well water supplied to their tenants and provide their tenants with a written copy of the results. Test results are provided to homeowners by the laboratory performing the analyses and are also sent to the New Jersey Department of Environmental Protection (NJDEP). The NJDEP notifies the local health agency when a well within its 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. Nitrate is required to be tested for in private wells in all 21 New Jersey counties.

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: [https://www13.state.nj.us/DataMiner] 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: [http://www.nj.gov/dep/watersupply/pw_pwta.html] Private Well Testing Act Frequently Asked Questions: [http://www.nj.gov/dep/watersupply/pwta/pwta_faq.htm] NJ Private Well Testing Act Data Summary, by county, municipality, and 2 mile by 2 mile grid: [http://arcg.is/1CPkHyC] NJDOH Drinking Water Facts: Private Wells, [https://www.nj.gov/health/ceohs/documents/pw_faq.pdf] NJDOH Drinking Water and Public Health Project, [http://www.nj.gov/health/ceohs/sanitation-safety/drinking-water-public-health/] 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.

Health Program Information

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, health effects of nitrate in drinking water, and other water safety issues, contact the United States Environmental Protection Agency Safe Drinking Water Hotline at (800) 426-4791.

Data Notes

Data Source: Private Well Testing Act Program, New Jersey Department of Environmental Protection, Well Test Results for September 2002-December 2018.   **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.

References and Community Resources

Under certain conditions, the body changes nitrate into nitrite. Methemoglobinemia, a form of anemia, can result from the reaction of nitrite with hemoglobin in the blood. When this occurs, the ability of the blood to carry oxygen to the body's tissues is decreased. In infants, this condition is one of the causes of "blue baby" syndrome. Infants are especially susceptible for four reasons: 1) their fluid intake per body weight is greater than that of adults; 2) their stomach acidity can be lower than adults, thus allowing the growth of stomach bacteria that change nitrate into nitrite; 3) they have a form of hemoglobin that is more likely to form methemoglobin; and 4) they are less able to change methemoglobin back into normal hemoglobin. Pregnant women are also more susceptible to nitrate-induced methemoglobinemia since they have higher than normal levels of methemoglobin. Nitrate can form a variety of N-nitroso compounds by reacting with proteins in the stomach. Some of these compounds have been found to cause cancer in animals. However, according to the USEPA, the data are inadequate to determine whether exposure to nitrate and nitrite in drinking water can result in human cancer. U.S. EPA's guide to drinking water from household wells: [https://www.epa.gov/privatewells]