What is the base-line flush rate for a water closet?

The baseline flush rate for a water closet, commonly referred to as a toilet, is typically 1.6 gallons per flush (GPF) for modern, efficient models in the United States. Older toilets may have flush rates of 3.5 to 7 GPF. Newer high-efficiency toilets can use as little as 1.28 GPF while still effectively clearing waste. These standards help conserve water while maintaining functionality.