Reduced / Sequestered
(To Implement Solution)
Using water at home—to shower, do laundry, soak plants—consumes energy. It takes energy to clean and transport water, to heat it if need be, and to handle wastewater after use. Hot water is responsible for a quarter of residential energy use worldwide. Efficiency can be improved household-by-household and tap-by-tap.
In the United States, 60 percent of home water use occurs indoors, primarily for toilets, clothes washers, showers, and faucets. Low-flush toilets and efficient washing machines can reduce water use by 19 and 17 percent respectively. Low-flow faucets and showerheads and efficient dishwashers can also contribute. In total, these technologies can reduce water use within homes by 45 percent.
30 percent of home water use occurs outdoors, while another 10 percent is lost to leaks. Water use for irrigation can be reduced or eliminated by using captured rainwater, shifting to plants that do not require it, installing drip irrigation, or turning off the spigot entirely.
Local restrictions on water consumption and policies requiring efficient plumbing are highly effective. Product labeling can inform consumer choices, while incentives, namely rebates on purchases of efficient appliances and fixtures, can encourage voluntary action.
Adoption of low-flow taps and showerheads at an 81–92 percent rate by 2050 (up from 59 percent of estimated market) could reduce carbon dioxide emissions by 1–1.6 gigatons by reducing energy consumption for heating wasted water. This would cost US$1.4–2.3 billion and avoid an impressive $468–765 billion in water heating costs over unit lifetimes. Scaling other water-saving technologies would drive additional reductions. We model hot water only in order to calculate energy savings.