Water productivity can also be improved by reducing the volume of water used to produce a fixed value of goods and services. A modeling study of the water supply system in Florianopolis, Brazil, concluded that replacing single-flush
toilets with dual-flush toilets would reduce municipal water use in the city by 14 to 28% and
reduce energy use at upstream (drinking water) and downstream (wastewater) treatment plants by
4 GWh year–1—enough energy to supply 1000 additional households (34). An analysis of 96 owner-occupied single-family homes in California, Washington, and Florida concluded that the installation of high-efficiency showerheads, toilets,and clothes washers reduced household use of municipal water by 10.9, 13.3, and 14.5%,