Nonpoint source water pollution (NPS)—  polluted runoff—results when precipitation interacts with pollutants to carry them over the surface of the ground or leach them into the ground water. It is pollution that cannot easily be “turned off” by technology. Rather, people must change habits and practices that affect the quality of our water.  The key to controlling nonpoint source pollution is prevention: wise use of fertilizer and pesticides, controlling what flows into the gutters and storm drains, not over-watering gardens and fields, disposing of pet waste away from water courses, and other preventive measures.

For more general information, go to the U.S. Environmental Protection Agency's site further defining nonpoint source and providing many links to information and activities.