A variety of pollutants are found in wash water generated from commercial car wash facilities. These pollutants include:
- Lead from break linings and tires
- Zinc from tires and breaks
- Detergents
- Oil/grease
- Lubricants
Although wash water contains these and many other pollutants, it is not as much of a stormwater concern as is the wash water created from washing your car in your driveway is. This is because commercial car washes are required to discharge their wash water to a sanitary sewer, where it is treated before being discharged into local water bodies. Some locations also reuse wash water, thereby conserving water.
Best Management Practices for Commercial Car Washes
Although commerical car washes already implement some BMPs, there are many others that can also be implemented to conserve water, prevent wash water from entering storm drains, and reduce the amount of pollutants entering the sanitary system. Here are a few.
- If floor drains are used in car wash bays they should discharge to a sanitary sewer, not a storm drain.
- Soapy water should be pretreated before it reaches the sanitary sewer line.
- Treat and recycle wash water
- Use an oil/water separator or other filtering device to trap leaking automobile fluids.
- Construct a berm aroun wash bays to contain soapy water and prevent it from infiltrating nearby storm drains. A speed bump before and after entering each bay could keep wash water contained.
- Remove unnecessary hoses to discourage spraying of floors and paved areas.
- Purchase non-toxic or the least toxic cleaners and products. Use biodegradable detergents that do not contain phosphates.
In depth BMPs for commerical car washes are outlined in Salt Lake City's Department of Public Utilities, Water Conservation Master Plan. View this document by clicking here.