Car Wash Girls

Contamination of surface waters arises from the rinseate discharging to storm drains, which in turn most commonly drain to rivers and lakes. Chief pollutants in such wash-water include phosphates; oil and grease; and lead. This is almost exclusively an issue for home/driveway washing, and parking lot style charity washes. Professional carwashing is a "non-point source" of discharge that has the ability to capture these contaminants and have them undergo treatment before being released into sanitary systems. (Water and contaminants that enter storm water drains does not undergo treatment, and is released directly into rivers, lakes and streams.)
Soil contamination is sometimes related to such surface runoff, but more importantly is associated with soil contamination from underground fuel tanks or auto servicing operations which commonly are ancillary uses of car wash sites — but not an issue for car washing itself.
For these reasons, some state and local environmental groups (the most notable being the New Jersey Department of Environmental Protection) have begun campaigns to encourage consumers to use professional car washes as opposed to driveway washing, including moving charity car wash fund raisers from parking lots to professional car washes.