GoudyL said:No its not. You can dump your waste water on the ground or you can dump it down a sanitary sewer (e.g pour it into a toilet).
He made an explict choice to dump commercial wastewater into a storm drain which is untreated rather than a sanitary drain which is treated.
If you aren't comfortable pouring your wastewater on the ground, then why are you dumping it into a storm drain? Out of sight, out of mind?
Car wash soaps and related surfactants are hardly mild.
The issue isn't the mild soap per se (although that's an issue too) its all the crap carried along with the "mild" soap as well as the interactions of that "mild" soap with other components in the waste water.
Car wash effluent can be very "strong" and isn't the sort of thing that should be dumped into storm sewers.
I'm talking about after you wash the car with a soapy mitt then hose it down, that water will be washed into the storm drain next time it rains.