In Fairfax County, the storm drainage system is separate from the sanitary sewer system. Storm drains convey stormwater runoff directly to local creeks and streams. Runoff is not treated before entering the waterways.

Car wash water may contain oils, greases, detergents and other materials that pollute water and harm fish and wildlife that live in streams.

Fairfax County's Erosion and Stormwater Management Ordinance (Chapter 124.1, Article 10 Section 3 of the Fairfax County Code) prohibits unpermitted commercial car wash water from entering the storm drainage system or streams. Businesses must comply with this regulation.

Currently, individual residential car washing is exempt from this regulation. Residents are encouraged to use the recommendations, listed below, to reduce the impact on the environment.

Car washing as a noncommercial fundraising activity is permitted by the Code of Virginia Title 15.2-2114.1 if the washing uses only biodegradable, phosphate-free, water-based cleaners as described below.