By using a hose nozzle and turning off the water while you wash your car, you'll save more than 100 gallons of water.
To save even more water, use a 3-gallon bucket of water to wash the car. Only use the hose to rinse.
Protect your drinking water from backflow:
Never submerge your hose in your bucket. A change in water pressure could suck the soapy water back into your household plumbing. This is called backflow. Backflow can contaminate the water you use to drink and bathe.
Install a hose bib vacuum breaker on all outdoor faucets. This little device prevents backflow. It's easy to install and costs only a few dollars. Most hardware stores carry them.