Mercer County Public Health Profile Report
Nitrate in Private Wells: Percent of Wells Exceeding Nitrate MCL, September 2002 through December 2018
Mercer1.6 95% Confidence IntervalNADescription of the Confidence IntervalThe confidence interval indicates the range of probable true values for the level of risk in the community.
A value of "NA" (Not Available) will appear if the confidence interval was not published with the NJSHAD indicator data for this measure.
State NA U.S. NANA=Data not available.
Mercer Compared to State
Description of Gauge
Description of the GaugeThis graphic is based on the county data to the left. It compares the county value of this indicator to the state overall value.
The county value is considered statistically significantly different from the state value if the state value is outside the range of the county's 95% confidence interval. If the county's data or 95% confidence interval information is not available, a blank gauge image will be displayed with the message, "missing information."NOTE: The labels used on the gauge graphic are meant to describe the county's status in plain language. The placement of the gauge needle is based solely on the statistical difference between the county and state values. When selecting priority health issues to work on, a county should take into account additional factors such as how much improvement could be made, the U.S. value, the statistical stability of the county number, the severity of the health condition, and whether the difference is clinically significant.
- Excellent = The county's value on this indicator is BETTER than the state value, and the difference IS statistically significant.
- Watch = The county's value is BETTER than state value, but the difference IS NOT statistically significant.
- Improvement Needed = The county's value on this indicator is WORSE than the state value, but the difference IS NOT statistically significant.
- Reason for Concern = The county's value on this indicator is WORSE than the state value, and the difference IS statistically significant.
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.
NoteData 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.
Measure Description for Nitrate in Private Wells
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