Nonpoint source pollution is harder to control than the point source water pollution.
Some water pollution is emitted from “point sources” that is discrete locations, from which pollutants are discharged, e.g., a pipe, ditch, ship, or factory smokestack. Point sources originate in large – and easy to trace – facilities, hence easier to control. In contrast, pollution from “nonpoint” sources is cumulative, arising from multiple inputs over larger areas, such as farms, city streets, and residential neighborhoods. Hence such sources are harder to precisely identify, and because of this uncertainty, nonpoint source pollution is harder to control than the point source.