Treat and recycle or reuse the water within your shop. Close the drain, unless it is needed to comply with state or local laws. In your vehicle washing operation, collect wash water and rinse water in a holding tank, filter and reuse. Clean water is only necessary for final rinse. The less foreign materials in your wastewater, the easier it is to pretreat or treat.
Pressure washers clean vehicle parts with hot water and detergent at high pressures.
The wastewater generated by this process is not hazardous. Contact local wastewater authorities prior to purchase, to see if any local regulations restrict hot soap wastewater discharge to the sanitary sewer. Reduces solvent use. In larger shops, this may be an economical way to remove dirt, oil, and grease from parts. The oven burns off the oil and then burns off the airborne particles before release into the atmosphere.