Background: 2018 bills, AB 1668 and SB 606, laid out a new long-term framework for water conservation in California. The bills direct the California Department of Water Resources and the State Water Resources Control Board to create new standards of water use for residential, commercial, and industrial use cases, and to develop water use budgets for water utilities based on these new standards. The legislation also outlines the need for budget variances in specific use cases that could materially impact a supplier’s ability to meet its budget requirements. Two such high-impact use cases are (1) a high percentage of residential customers using evaporative cooling systems and (2) a high percentage of seasonally occupied residences.
Residential Evaporative Cooling
Project: CWEE will evaluate the water and energy consumption of residential evaporative cooling systems to assist DWR in creating allowable water budget variances for water utilities with a high percentage of residential customers using evaporative coolers. CWEE will provide water metric estimates for each climate zone on a spatial map for California. Further, researchers will perform an observational study using measured customer water and energy data to identify homes with evaporative coolers and estimate the average water consumption of the cooling systems. The resulting research will summarize and recommend protocols and procedures for other organizations to perform evaluation depending on the level of water or energy data available to their agency.
Geographic location of study: San Bernardino County Service Areas
Seasonally Occupied Residences
Project: Water utilities with large amounts of seasonally occupied homes, such as vacation homes or vacation rentals, will be disadvantaged when the State Water Boards begin to enforce residential water use standards, which are based only on a permanent population. CWEE will provide methods to evaluate and verify the number of seasonally occupied residences (e.g., vacation rentals) in water utility service territories to assist DWR in creating allowable water budget variances for water utilities with a high percentage of seasonally occupied residences. Researchers will consider a range of approaches and methods based on the spatial specificity desired (i.e., individual homes or an estimate of total homes) and customer-level data available (water billing only, AMI consumption only, or water and energy billing) to entities who may be performing this analysis. CWEE will generate methodologies for each scenario, assess the implementation and application of the methods, and develop recommendations to DWR for the development of appropriate variances for seasonal populations.
Geographic location of study: Vacation communities in Sacramento, South Lake Tahoe, Coachella Valley, and Lake Arrowhead
