What is point and nonpoint source pollution?
Point source pollution is commonly defined as water pollution that can be traced to a specific source of discharge such as a pipe. Nonpoint source (NPS) pollution is more difficult to define. A simplified definition would be water pollution that does not discharge from a pipe. Examples include, but are not limited to, runoff from construction sites and agriculture, silviculture, mining and urban areas. Nonpoint sources of pollution can come from any area, and most do not discharge at a specific, single location. In general, nonpoint pollutants are carried over and through the ground by rainfall, runoff and snowmelt. Legal distinctions complicate the definition, however. When runoff is collected and discharged through a pipe (such as combined storm and sanitary sewers, or in cases of runoff from active mines), it is usually considered to be a point source.
