What is the consumptive use of the various methods of car washing? Here’s a report from News8Austin. From the article:

Dean Minchillo, water conservation specialist from the Lower Colorado River Authority, did an experiment involving hand washing versus car washing. “We took a small meter and attached it to a spigot for a garden hose and then actually washed a vehicle by hand in a driveway and then took those numbers and compared them to what type of usage you might see in some of the other commercial type of car washes,” he said.

The results :

• Self-service car washes typically use about 17 gallons per vehicle, depending on the type of nozzle on it

• In-bay car washes, at gas stations, use about 20 to 40 gallons per vehicle

• The full service car washes can use up to 60 gallons per vehicle

• Washing it on [your] own, in the driveway, can take more than 100 gallons per vehicle

“A regular garden hose, if it is left open, it will use about 10 gallons per minute of water.