In Los Angeles, there are many storms drains which have been marked with 'Do Not Dump: This Drains To Ocean' or something to that effect. These markings often accompany the picture of a skeleton of a dead fish and were funded by such organizations as Heal The Bay and Surfrider Foundation. In Los Angeles, and presumably most areas, storm drain runoff discharges directly into rivers and the ocean, where oils, garbage, etc which are dumped in the street end up. Therefore, a car which is leaking oil or radiator fluid may indeed kill fish in the future. This effect is most notable during the first large storm after the dry season in Los Angeles, which washes 4-6 months of oil accumulation into the ocean. After these storms the beaches are often closed, and fish kills are not uncommon