If you wash your car over your driveway, use a bucket for your sponge and soapy water. This prevents the excess soap from flowing into the storm drain. When you’re done, pour the dirty water into either a toilet or a sink. Don’t dump it out into the street. Otherwise, all the oil, exhaust fume residue, brake pad dust, and soap chemicals run off the hard surface and flow directly into the stormwater drains. A stormwater system doesn’t filter and treat water the way your wastewater system would. Instead, it flows into the watershed polluting our water bodies.
Most importantly, attach a nozzle with flow restriction to your hose. This will minimize water use and water runoff. Don’t commit the sin of letting the water gush out of your hose into the driveway while you’re distracted. Be water wise!