Vehicle wash water may contain oil, grease, metal (paint chips), phosphates, detergents, soaps, cleaners, road salts, sediment, and other chemicals that can contaminate source water. Vehicle wash water can carry contaminants and sediments to surface waters through storm drains and can contaminate ground water by infiltration or drainage to subsurface wells (injection wells) or septic systems. Coin-operated, manual car washing facilities can be particularly concerning because an attendant is not usually on site to monitor the products used or what is disposed of down the drain.