The modern toilet in the United States is in a classification known as the Low Flow Toilet. In 1992, U.S. President George H. W. Bush signed the Energy Policy Act which made the 1.6 gallons per flush a mandatory federal maximum for new toilets. Low-flow toilets use 1.6 gallons or less per flush as opposed to 3.5 gallons. Early low flow toilets were problematic. Since the turn of the century the low flow toilet has improved a great deal.