Why do toilets flush on 1.6 gallons of gallons of water?By
Seems oddly precise to have the law limit the amount of water used in toilet flushing to 1.6 gallons. Where did 1.6 come from? What not a nice round number such as 1.5 gallons?
The odd number comes from the origins of low-flow toilets. 1.6 gallons equals 6 liters, the amount of water commonly used in toilets across Europe and Asia at the time the US Energy Policy Act of 1992 was in development.