Optimum no rinse
http://www.autogeek.net/optimum-no-rinse.html
You can wash your car with only 2 gallons of water. It's like a cross between quick detailing and full on washing your car. You put a few capfulls into a 2 gallon bucket and dip your sponge into the water and then wipe your car down, then use a microfiber towel to dry. Use warm water and wash your in your garage.