Just today, I used ONR to wash my daily driver (unusually warm November mid-Atlantic weather). I used between 1.5 -2 gallons of water for the wash. I separately used a garden sprayer (about 1 gallon pressurized) to help rinse off the wheels (used Eagle One Wheel Cleaner). So for today, 3 -3.5gallons of water, 2 MF towels to dry, 1 MF towel for application of spray wax (booster) for a quick detail with very minimal runoff. I figured I have used a total of between 30-36gallons for the season.