Abstract

This study examines water demand in 19 public water systems in Salt Lake County, Utah, USA, including the metropolitan and economic center Salt Lake City, as water users adjusted to sudden shifts in work and social activities due to the COVID-19 pandemic. We develop water demand models based on climate and population during a pre-COVID period and evaluate whether these models hold for the initial pandemic year 2020 and beyond (2021) by comparing predicted and observed water demands. Our analysis captures a shift in water demand away from Salt Lake City into surrounding communities and from non-residential to residential settings. During 2020, total countywide water demand rose by 8.5% overall. In Salt Lake City, residential water demand rose by 5.3% while non-residential water demand fell by 4.9%; in the rest of the county, residential water demand rose by 14.5% while non-residential water demand rose by 2.9%. We attribute the redistribution of water demand to stay-at-home activity during much of 2020. The observed post-pandemic shifts demonstrate how water demands can quickly and substantially deviate from historic conditions. Additionally, poor model performance for demands in 2021 indicate that the temporary but major disruption of the pandemic may have resulted in a more sustained, long-term shift in water demands. Municipal water systems may benefit from planning scenarios that consider the scale (magnitude and persistence) of corresponding impacts on hydraulics, water quality, and revenue.