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.

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.