75E - PH - WATER MANAGEMENT PLAN

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2015 URBAN WATER MANAGEMENT PLAN efficiency clothes washers. It also assumes the implementation of future active measures, assuming the implementation of Metropolitan incentive programs at historical annual levels seen in Orange County. 2.4.1 Demand Projection Methodology The water demand projections were an outcome of the Orange County (OC) Reliability Study led by MWDOC where demand projections were divided into three regions within Orange County: Brea /La Habra, OC Basin, and South County. The demand projections were obtained based on multiplying a unit water use factor and a demographic factor for three water use sectors, including single - family and multi- family residential (in gallons per day per household), and non - residential (in gallons per day per employee). The unit water use factors were based on the survey of Orange Oounty water agencies (FY 2013 -14) and represent a normal weather, normal economy, and non - drought condition. The demographic factors are future demographic projections, including the number of housing units for single and multi - family residential sectors and the total employment (number of employees) for the non- residential sector, as provided by CDR. The OC Reliability Study accounted for drought impacts on 2016 demands by applying the assumption that water demands will bounce back to 85 percent of 2014 levels (i.e. pre- drought levels) by 2020 and 90 percent by 2025 without future conservation, and continue at 90 percent of unit water use through 2040. The unit water use factor multiplied by a demographic factor yields demand projections without new conservation. To account for new implementation of conservation, projected savings from new passive and active conservation as a result of plumbing codes, water model efficiency landscape ordinance, and rebates from Metropolitan were excluded from these demands. As described above, the OC Reliability Study provided demand projections for three regions within Orange County: Brea /La Habra, OC Basin, and South County. The City's water demand represents a portion of the OC Basin region total demand. The City's portion was estimated as the percentage of the City's five -year (FY 2010 -11 to FY 2014 -15) average usage compared to the OC Basin region total demand for the same period. 2.4.2 Agency Refinement Demand projections were developed by MWDOC for the City as part of the OC Reliability Study. The future demand projections were reviewed and accepted by the City as a basis for the 2015 UW MP. 2.4.3 25 Year Projections A key component of the 2015 UWMP is to provide insight into the City's future water demand outlook. The City's current total water demand is 36,655 AFY, met through locally pumped groundwater and purchased imported water from Metropolitan. Table 2 -4 is a projection of the City's water demand for the next 25 years. 75E -27 arcadis.com 2 -7