Nonpoint source pollution includes many small sources, like septic tanks, cars, trucks, and boats, plus larger sources, such as farms, livestock ranches, and timber harvest areas. Pollution that comes from a single source like an oil or chemical spill is known as point source pollution.Often this type of pollution has large impacts but fortunately they occur less often. Discharge from faulty or damaged factories or water treatments system are also considered point source polluters.ollution that comes from a single source like an oil or chemical spill is known as point source pollution. Often this type of pollution has large impacts but fortunately they occur less often.