Welcome to the world of water recovery! A good tip is to have your wash water tested. All you have to do is contact the local sewer authority where work is being done and ask for permission to discharge into their sanitary sewer drain. Some are more difficult to deal with than others. Typically they will want to see lab test on the following: BOD, TSS, Total Oil & Grease, & Metals. Also a PH reading at time sample is collected. They will always welcome a high PH opposed to a low PH. Most of the time it is free to do this unless you need a NON-Hazardous Waste Manifest. Hopefully this helps...

Stevie
Superior Exteriors
Fleet Cleaning Services
Georgia, South Carolina, & North Carolina