Septic Systems and Nitrate Nitrogen as Indicators of Ground Water Quality Trends in New Jersey

Controlling ground water quality is a major environmental goal for New Jersey citizens. Controlling nitrate nitrogen in ground water is particularly important because of the risk it poses to human health, and because of its ability to enter streams and lakes and to enhance the harmful process of eutrophication. In order to control nitrate levels in ground water and surface water, it is necessary to control where and how septic systems are constructed, because nitrate nitrogen is a natural component of onsite waste disposal (septic system) effluent. By reviewing United States census data, it is possible to evaluate onsite waste disposal nitrate loading trends. Between 1970 and 1990 New Jersey’s population increased by more than 500,000 persons; a 7.1% increase. During this same period, the number of onsite sewage disposal systems (septic systems) in the state decreased by about 70,000; a 16% decrease. The decrease in the number of onsite disposal systems is probably the result of municipal sewer system construction projects that proliferated during those same years. When viewed on a statewide basis, there now are fewer septic systems and decreased nitrate mass loading, but this is not true for all counties or municipalities. Counties that were primarily rural in 1970 have become more developed and nitrate mass loading from the septic systems has increased since 1970. These developing counties are at risk from new nitrate loading from septic systems and from associated impacts of suburban development. Without careful planning, increased nitrate loading from septic systems is likely to create additional burdens on ground water and surface water in these rapidly developing areas of the state.