Offsetting water conservation costs to achieve net-zero water use

摘要

Achieving net-zero water use (in which annual potable water use is no greater than annual rainfall) and achieving reasonable payback periods for water conservation measures were investigated for a proposed housing development in Davis, Calif. Water efficiency scenarios were analyzed for indoor and landscape watering use, along with the use of graywater and rainwater on landscaping. Potential cost savings were found in both water utility energy conservation and energy reductions associated with decreases in hot water use. The feasibility of selling carbon offset credits in California's cap-and-trade program by reducing greenhouse gas emissions associated with the water-energy nexus was also investigated. Results indicated the feasibility of achieving net-zero water use at the scale of a single-family residence and the entire community through indoor and landscape water conservation measures alone.