Stay-at-Home Orders during the COVID-19 Pandemic Reduced Urban Water Use.

In response to the outbreak of the COVID-19 pandemic, many governments instituted "stay-at-home" orders to prevent the spread of the coronavirus. The resulting changes in work and life routines had the potential to substantially perturb typical patterns of urban water use. We present here an analysis of how these pandemic responses affected California's urban water consumption. Using water demand modeling that fuses an integrated water use database, we first simulated the water use in a business-as-usual (non-pandemic) scenario for essentially all urban areas in California. We then subtracted the business-as-usual water use from the actual use to isolate the changes caused solely by the pandemic response. We found that the pandemic response decreased California's urban water use by 7.9%, which can be largely attributed to an 11.2% decrease in the commercial, industrial, and institutional sector that more than offset a 1.4% increase in the residential sector. The influence of the stay-at-home practices on urban water use is slightly stronger than the combined influences of all non-pandemic factors. This study covers both metropolitans and suburbs; therefore, the results could also be useful for analysis of the impacts of COVID-19 on water use in other urban areas.