As far as I'm aware Mike, car wash sites have to have drainage which runs into the main sewer (foul drain). This would be dealt with during the planing/construction stage.
As for biodegradeability, for this to happen, oxygen is needed, which is absorbed from the water. A product which is highly biodegradeable will absorb oxygen more quickly and so degrade more quickly. This can and does create problems for fish and other life forms.
As for road pollutants running into the storm/land/river drainage systems, this does happen extensively. Spilt diesel fuel and oil on our roads is a major contributor to this type of pollution. I think that the authorities/water companies realise that they will only be able to contain rather than prevent the problem. The regulations which we are required to observe are one of the tools for containing the problem.
Perhaps, because I have grown up in a rural and agricultural environment, and have first hand experience of the consequences of different types of pollution, I probably embrace this topic more passionately than others. If I come over in a "Holyer than thou" type way, please forgive me, it's just the passion taking over.
Safe and happy cleaning:)
Ken