“Point source” is defined as pollution coming from a single source, such as an industry or wastewater treatment plant. “Point source” is a discrete conveyance of an effluent’s discharge usually through pipes or man-made ditches into a receiving stream. The Clean Water Act put restrictions on how much and what kind of pollutants can be disposed of into the rivers and lakes. Thus usually all “Point sources” are regulated through the National Pollutant Discharge Elimination System (NPDES) via a permit issued from the EPA or the designated state authority.
“Non-point source” is pollution which does not have a specific source such as an industry or sewage treatment plant but comes from many diverse sources. “Non-Point Source” pollution comes from the cumulative effect of a region’s residents going about their everyday activities. “Non-Point Source” pollution is caused by rainfall or snowmelt moving over and through the ground. As runoff moves, it picks up debris which contains pollutants and deposits them into the lakes, creeks and rivers. The following are several sources of “Non-Point Source” pollution:
- Excess fertilizers, herbicides, and insecticides from agricultural lands and residential areas;
- Oil, grease, and toxic chemicals from urban runoff and energy production;
- Sediment from improperly managed construction sites, crop and forest lands, and eroding stream banks.
- Salt from irrigation practices and acid drainage from abandoned mines;
- Bacteria and nutrients from livestock, pet wastes and faulty septic systems.