2025 Orange County Water Demand Projection Model
Table 4-3: Future Model Parameters and Assumptions for Baseline Demand Forecast
Data Category
Variable
Source
Assumptions
Historical households per account; averages are multiplied by households projected by CDR Accounts are assumed to be constant into the future
Single-family and multifamily accounts
CDR
Driver Units
Agency Billing Data
Irrigation accounts
Proportion of jobs within CII sectors projected by CDR
Sectoral employment
CDR
Monthly Maximum Temperature and Total Precipitation
PRISM
30-year historical normal weather
Prices increase by 3% per year above inflation for 2025-2030 and keeps pace with inflation thereafter (zero difference from inflation trend)
Water Price
Retail Agencies
State & Local Restrictions
Water Use Restrictions
None
Sine/cosine functions to capture monthly pattern Constant income at 2022 value (real dollars) Derived from CDR housing unit projections, assuming residential area remains at 2024 levels
Seasonality
Median income
US Census
Explanatory Variables
Housing density
CDR
Persons Per Household
CDR
CDR projected demographics
Federal Reserve
Gross Domestic Product
Long-term GDP trend
Relative Sectoral Employment Passive Efficiency Estimates
CDR
Calculated based on CDR projections
Assumes a 2% decrease in residential demand due to conservation by 2030 (linearly extrapolated), then no change None (occurred between March 2020 and May 2023)
Flume Insight
COVID Binary Indicator
Future assumptions were defined for every element of the water demand models, including sectoral driver units and explanatory variables.
4.2 Development of Forecast Inputs
Data sources documented in this section are limited to projected future datasets.
4.2.1
Retailer Driver Units
Driver units reflect the size or scale of a water use sector and allow for differentiation of the rate of use from total consumption. CDR provided the Orange County Projections 2022 (OCP-2022) as an update of the 2018 Orange County Projections. OCP-2022 estimates single-family residential housing units,
4-4
Appendix G - 57
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