New Report Finds Opportunities for Improving Long-Range Water Demand Forecasts

August 5, 2020, Oakland, California – A new report from the Pacific Institute, An Assessment of Urban Water Demand Forecasts in California, finds that urban water suppliers in California routinely overestimate long-range water demand.

“While there’s a widespread perception that population and economic growth inevitably increase water use, this has not been the case in California for decades,” says report author Heather Cooley, Director of Research at the Pacific Institute. “While water suppliers projected per capita demand would decline by about one percent a year, we found demand declined twice as fast. As a result, the water suppliers overestimated future demand, which can result in unneeded water supply and treatment infrastructure, higher costs to ratepayers, and unnecessary adverse environmental impacts.”

An Assessment of Urban Water Demand Forecasts in California finds that per capita water demand declined between 2000 and 2015 for all 10 water suppliers examined. In most cases, reductions in per capita water demand were so large that total water demand declined during this period. All water suppliers overestimated demand, largely due to inflated estimates of per capita water demand and, to a lesser extent, to overestimates of population growth.

The report offers recommendations on how to improve the accuracy of long-range water demand forecasts, including developing guidelines and standards for urban water demand forecasts and examining water use trends.

Learn more and download the report here