Have you never used a garden hose? Do you know that a regular, average hose left running overnight can waste like 5,000 gallons of water? My HOA enforces a rule - you must keep at least two trees per household. Trees need water. Not that much, of course, I shared the overnight hose number just for the sense of measure. Now you do the math - couple of trees, bathrooms, showering, drinking, cooking - that water usage adds up.