Toilets flush differently around the world, and those differences matter for water supply. In the United States, many toilets use a loud, siphon-driven whoosh that relies on a strong surge of water to create suction and carry waste away. Across much of Europe, manufacturers and consumers favor lower-volume options or designs that avoid suction altogether; some German and Dutch toilets even have a ceramic shelf above a small water pool.
How a toilet flushes affects household water use at scale. Facing more frequent droughts and growing strain on supplies—especially in the American West—conserving water in homes is increasingly important. The U.S. addressed this in 1992 with a federal law capping new toilets at 1.6 gallons per flush (gpf). Industry estimates say that change saved roughly 18.2 trillion gallons (68.9 trillion liters) over the next two decades.
The Trump administration sought to unwind those gains. It issued a directive pausing enforcement of the 1992 standard and urged Congress to repeal the law. House Republicans also advanced the “Don’t Mess With My Home Appliances Act,” a bill intended to make it easier for the Department of Energy to weaken energy and water-efficiency rules for appliances. That measure faces long odds in the Senate.
Water experts say rolling back standards would be short-sighted. Samuel Sandoval Solis, a water-resources specialist at UC Davis, warned that loosening rules would undermine hard-won progress in changing American habits around water use. Villanova environmental engineer Metin Duran pointed to broader cultural differences: the U.S. is more resistant to regulatory mandates than many European countries where efficiency standards have greater public acceptance.
Some complaints about low-flow fixtures persist—most prominently from President Trump, who has said low-flow toilets and faucets perform poorly and force people to flush multiple times. Experts counter that early models had issues, but modern fixtures undergo rigorous testing and perform reliably. Ron Burke of the Alliance for Water Efficiency says the flushing problems people recall are largely a thing of the past.
Still, many older, inefficient toilets remain in U.S. homes. A 2019 Plumbing Manufacturers International study found more than one in five U.S. toilets use 3.5 gpf or more; some models installed before 1980 use five gallons or more per flush. In drought-prone California, PMI estimates about 2.4 million legacy toilets are still in use; replacing them with efficient models could save roughly 14.1 billion gallons of water.
With long-term threats such as megadroughts, declining Colorado River flows, and reservoirs well below normal, officials and water managers argue that preserving and strengthening federal water-efficiency standards is aligned with national water-security needs.