The large volumes of wastewater generated in the United States can be a serious threat to public health and the environment if the wastewater is disposed of improperly. People use more water than ever before due to the increasing number of labor-saving appliances and to changes in life-styles. Automatic clothes washers and dishwashers, higher standards of personal cleanliness, and automatic water supplies add great volumes of water to the average daily flow of wastewater from a home.

Those people living outside municipalities often use on-site systems for disposal of this wastewater. Because water use is increasing, on-site systems must handle ever-greater volumes of wastewater. Additionally, much of the land now being developed for suburban and rural housing is less capable of supporting on-site systems. Thus, we are facing a situation in which more on-site systems capable of handling larger volumes of wastewater are being installed, yet less-suitable sites are frequently chosen for these systems.

To help in addressing these complex problems, this chapter provides basic information about on-site wastewater systems and their management. The first section of this chapter discusses how the increasing volume of wastewater and the development of less-suitable land affect us. The second section covers some of the history of on-site wastewater management. The last section presents the basic science of on-site wastewater treatment and disposal. Information about the science of on-site treatment and disposal provides the background for the following chapters, which cover more detailed aspects of on-site systems.

From the North Carolina Onsite Guidance Manual