Septic systems are widely used in North Carolina. According to the 1990 census data, of 2,818,193 total households counted in the state, 1,403,033 households were served by public sewers, while 1,365,632 households were served by septic tank systems and 49,528 had other means of disposal. This means that nearly 50 percent of North Carolina's households use septic tank systems.

Select a watershed of interest in the map below to learn about density distribution and statistics of septic tank systems or view a statewide summary of sewage disposal and potential nitrogen contributions of septic systems to surface and ground water.