Eliminating outdoor cleaning of pavements and cars is an excellent way to save water. The best way to clean outdoors is to get out the broom and sweep. The amount of water you save is, of course, determined by the amount of water you normally use for these purposes.
A typical hose runs at a flow rate of 5 to 8 gallons per minute (gpm), but can run as high as 10 gpm. If your hose runs at 7 gpm, then a five minute driveway hose-down uses 35 gallons of water and a 15 minute car wash uses 105 gallons of water.
Eliminating your weekly five minute pavement hose-down could save between 625 and 2500 gallons of water per year depending on the flow rate and frequency of use.
If your car desperately needs a bath, take it to a car wash that recycles water. You could also use some old rags and a bucket of water to do the job with much less water waste.
If you must hose down pavements or wash your car, be sure to attach a shutoff hose nozzle on your garden hose. A good quality hose nozzle should not leak or drip when in the off position. Check to make sure that your hose is not leaking at the hose bib connection either. A hose washer will usually take care of hose bib leaks.