What Is Nonpoint Source Pollution?

Nonpoint sources are often linked with agricultural, forestry, urban, and rural residential land use activities where rain or snow runs off to surface waters. As the runoff moves, it picks up and carries away natural pollutants and pollutants resulting from human activity, finally depositing them into lakes, rivers, wetlands, coastal waters, and groundwater. Polluted runoff causes damage to fish, wildlife, and their habitat; damages drinking water supplies; promotes excessive weed growth; and degrades Oregon's scenic beauty and recreational opportunities. Nonpoint sources continue to be a leading cause of significant water quality impacts across the state and the nation as a whole.

Nonpoint source pollution is briefly defined in Oregon Administrative Rule 340-41-006 (17) as: "diffuse or unconfined sources of pollution where wastes can either enter into or be conveyed by the movement of water to public waters." In Oregon, the most prevalent nonpoint source pollutants are temperature, sediment, bacteria, nutrients, heavy metals, pesticides, and other toxics.