If you’re flushing a toilet in the US, you likely hear a strong siphon-driven whoosh that creates suction to pull waste away. In much of Europe, toilets often offer lighter or stronger flush options and use less water; some German and Dutch designs even have a ceramic shelf above a water pool rather than relying on suction.
How toilets flush matters for water supply. With climate change intensifying drought and widespread water scarcity—especially in the western US—reducing household water use has become more urgent. The US’s siphon-style toilets historically required large volumes of water to create the suction effect. In response, a 1992 federal water-efficiency law limited new toilets to 1.6 gallons per flush (gpf), a change that industry estimates saved about 18.2 trillion gallons (68.9 trillion liters) over two decades.
President Donald Trump has pushed to roll back those standards. His administration issued a directive pausing enforcement of the 1992 limits and recommended Congress repeal the law. House Republicans passed the “Don’t Mess With My Home Appliances Act,” aimed at making it easier for the Department of Energy to weaken appliance energy and water rules, though the measure is unlikely to pass the Senate.
Environmental engineers and water experts say weakening standards would be a step backward as many communities confront declining water supplies. “It took us so long to actually make a small dent on the American mindset of saving water,” said Samuel Sandoval Solis, a water-resources expert at UC Davis, calling the proposal “backwards.” Metin Duran, an environmental engineer at Villanova University, noted cultural resistance to regulation in the US compared with greater public acceptance of such rules in Europe.
Trump has publicly complained about poor performance from low-flow fixtures, saying people are flushing multiple times and can’t get enough water from faucets. Experts counter that complaints date to early low-flow models and that modern fixtures undergo rigorous testing. “When the president complains about his toilets not flushing well—that’s a thing of the past,” said Ron Burke of the Alliance for Water Efficiency.
Still, many US homes retain older, inefficient toilets. A 2019 study from Plumbing Manufacturers International found more than one in five US toilets use 3.5 gpf or more; some pre-1980 models use five gallons or more per flush. In drought-prone California, PMI estimates about 2.4 million legacy toilets remain in use; replacing them with efficient models could save the state roughly 14.1 billion gallons of water. With long-term threats like megadroughts, dwindling Colorado River flows and reservoirs far below normal capacity, officials say preserving and improving federal water-efficiency standards aligns with the nation’s water-security needs.
Edited by: Jennifer Collins, Sarah Steffen