water pollution that originates from various or diffuse sources; examples include stormwater runoff and streambank erosion (see point-source pollution).
Water pollution whose sources cannot be pinpointed to a specific outfall or pipe but that can be best controlled by proper soil, water, and land management practices. Oil washed off street during rainstorms is an example of nonpoint-source pollution.
resulting pollution from a widely dispersed land area that is carried in runoff water from a field, forest, or urban area into a stream, lake, or groundwater
pollution from sources that are not specific, such as areas of timber harvesting, surface mining, and construction.
Pollution from sources that cannot be defined as discrete points, such as areas of crop production, timber, surface mining, disposal of refuse, and construction. From Glossary of Geology, 4th Edition, 1997, American Geological Institute.
Diffuse sources of water pollution, such as runoff from streets, farms, and mines.
Pollution that is generated over a relatively wide area and dispersed rather than discharged from a pipe. Common sources of nonpoint pollution include stormwater runoff, failed septic systems, and marinas.
A contributory factor to water pollution that cannot be traced to a specific spot; for example, pollution that results from water runoff from urban areas, construction sites, agricultural and silvicultural operations, and so forth (USEPA Region 5).