The Colorado River Basin services the residential water use needs of nearly 40 million people. Residential use is the largest component of water use in urban areas, with outdoor water use representing a significant portion of a household’s water use. The Colorado River Basin is facing water scarcity, so some cities have identified outdoor water use (especially non-functional turf) as a target for reductions. This study compiled the water use of over thirty urban Colorado River Basin Service area areas and separated the indoor and outdoor water usage. The outdoor water usage total was then examined for trends with explanatory variables (population, climate, water rates). Results show a large variability in outdoor water usage per capita between different population sizes and city locations. Still, there has been an overall downward trend of outdoor water usage in most large urban areas over the past decade. Our future work will include examining the effectiveness of water conservation policies in the river basin and modeling the effect of past changes in policy, climate, population, and water rates. This work can help quantify the amount of outdoor water usage for municipalities within the Colorado River Basin Service area and allow for urban areas to see the effects of various water use reduction efforts like watering restrictions and turfgrass replacement programs.
