Tell her you will now use new and improved water that defies gravity and now will flow uphill! Thus avioding her driveway. If the water does flow onto her driveway, explain that the old (flows downhill) water must be in the water system still and you probably need to wash your car once a week to use up the old water before the new water starts coming out of your hose.

 

I'm going to disagree with you on this Richard (with qualifications). In general terms the CWA is aimed at point sources of which individual homeowners are excluded. Additionally since discharge from homes usually goes through the water treatment facility (both storm water and sanitary discharge) the discharge of non-hazardous chemicals into the sewers in excluded as long as they are treatable. This would not apply if this discharge is from a business or if you were dumping directly into a stream, river, lake or ocean. Soaps and detergents that do not contain phosphorous are not categorized as hazardous.
Of course individual states can write tighter rules than the feds so in California who knows. Also, as stated above, if your effluent goes directly to a stream then that is different as well. Finally if your city uses a separate storm water system that discharges directly into surface waters rather than being treated then again that is an issue.

 

That's cool. I don't claim to be an expert or at all very knowledgeable about the CWA. Just something a lot of new detailers worry about when they go mobile.

Here in California, there are cities like Newport Beach that have very strict water laws about washing cars, and where I live, Mar Vista which is a part of Los Angeles City, I don't have the water restrictions as my neighboring cities like Culver City do. Like I said, the Act that was passed in 1972 says..somewhere in all the legalese...that it's up to each state and city to enforce this, and not many do..especially outside of California.

Richard

 

Everywhere I've ever lived, the storm water went directly into the nearest stream... no way to build a processing facility that would handle the volume of water we get in a big rainstorm around here... the bigger concern around here is runoff from people's lawns, which have all kinds of heinous stuff on them (like fire ant killer, rodent killer, many fertilizers, etc.). You could wash MANY cars and produce less nasty stuff for a stream than the runoff from one suburban lawn...

 

Older systems typically had separate storm water and sanitary pipes. Most towns here in the west are not that way and in fact do have issues when large storms dump on them.
Also today's soaps are much friendlier than yesteryear's. No more phosphate and usually breakdown readily in bioreaction. I agree with the statement about lawn crap - at least they banned Dursban, Diaznon, Chlordane. Also an issue is all the drugs (legit and otherwise) from peoples sewers. Seems there is a bit of carryover if you know what I mean. Enough said.
So yeah, washing our cars is a fairly benign activity in the grand scheme of life.

 

Just keep washing, and if she complains, do it in her driveway.