You shouldn't be washing your car in the driveway. Even if you use environmentally friendly soap, or no soap, the water coming of the car isn't exactly clean.
Professional car wash places are required (depending on location) to collect and dispose of their waste water in a safe way. When you wash the car in the driveway, the waste water will either go into the ground or the storm drains, neither of which will ensure that the waster is cleaned before reentering the environment.
I solved this problem in minimalist way - I wash my car maybe twice a year. It sits in my driveway in rain anyway because my garage is waiting for some spare time so that I can finally reuse all that pallets I collected since last year (mostly clean pallets I've already made some nice yard furniture for myself and family, all those pallets already have planned use but I don't have enough time).
For moving around town i just walk, maybe sometimes I use my 20yr old bike. My car is used only to travel from my town to nearest city, because it takes 3x more time to go with bus->train->taxi to where I need to go and is a little more expensive. Then it sits idle 5 days. It's more like 1.2tons and is not that guzzling, 7L/100km. Diesel or hybrid would be guzzling even less, but they break more and/or are more expensive. I'm not a eco freak, I do what I can, but some people really do need to own some transport. In Poland, if I see someone with a big pickup, it typically means he actually DO uses it to pick up various things otherwise it would be too inconvenient to own such a big car.
You said "mostly clean" and I assumed that this was about dirt and debris, and the stuff they're treated with is not visible. There is a stamp on the side which shows how they have been treated, though.
Yup, I worked at a car wash and the water coming off of cars is absolutely disgusting. Had to wear some sort of hazmat type suit to clean the trench as we called it.
We're gonna preserve our quality of life one exception at a time all the way to societal collapse, it seems. How much quality of life can we have when billions are on the move due to heat dead zones, collapsing one government after another?
