My/ourshop is in my mother in laws house with connected shop. Her water sewer trash bill for 3 months was over $300, WATER USAGE STATED 28,700 GALLONS. Single person, a couple dogs, and we might have washed 12 vehicles all together in that much time. City had been estimating usage for other a year cause the dogs (who are scared of men) were out in the yard. Just wondering how much water used to wash typical dirty vehicle would be? 100-200 gallons using just the hose, no power washer. I usually estimated 50-75 gallon do to the fact as floor drain is buried 55 gallon drum (french drain system), and figure we push out 20 gallon with sqeegie. Thanks RANDAL