My car hobby includes detailing, and for a number of years I have been going with Optimum No Rinse... it has been revolutionary. It safely (with the right technique) removes loose dirt off the car with just two buckets of water and no need to rinse... which makes it easy to do in a garage, apartment complex, wherever, you don't waste so much water and you don't drench these old rust prone cars with water.
check this link: http://www.detailedimage.com/Ask-a-Pro/wash-and-wax-in-60-minutes-featuring-optimum-no-rinse/
However, when a car is super soiled or I want to strip the wax off the car to clay bar/polish/re-seal, I'll get out the foam gun attachment to my hose and use Chemical guy's Citrus Wash and Clear.
Hope that helps