Contact your permitting authority for information about how vehicle wash water is being regulated in your area. The following questions are designed to help you find sources of storm water contamination from vehicle and equipment washing and to select BMPS to reduce those sources. Reading this section can help you eliminate, reduce, or recycle pollutants that otherwise may contaminate storm water. Also refer to Vehicle Washing BMP in Section 4.4. Phosphates, which are plant nutrients, can cause excessive growth of nuisance plants in water when they enter lakes or streams in wash water.
Some States ban the use of detergents containing high amounts of phosphates.
Contact your supplier about phosphate-free biodegradable detergents that are available on the market. Used wash water contains high concentrations of solvents, oil and grease, detergents, and metals. Try not to wash parts or equipment outside. Washing over impervious surfaces like concrete, blacktop, or hardpacked dirt allows wash water to enter storm drains directly or deposits contaminants on the ground, where they are washed into storm drains when it rains. Washing over pervious ground such as sandy soils potentially can pollute ground water.