2025 Orange County Water Demand Projection Model
Table 3-3: Single-family Regression Variables and Coefficients
Explanatory Variable
General Directional Influence
Model Coefficient Range
Persons per Household
+ +
0.32 0.52 -0.52 0.09 -0.12
Single-family Units per Account
Housing Density
-
Average Agency Income Marginal Price (per 10 CCF) Departure from normal monthly maximum temperature
+
-
+
0 to 0.93
Departure from normal monthly maximum temperature (lagged 1 month)
+
0 to 0.95
Departure from normal monthly precipitation Departure from normal monthly precipitation (lagged 1 month) Departure from normal monthly precipitation (lagged 2 months) Departure from normal monthly precipitation (lagged 3 months)
-
0 to -0.031
-
0 to -0.05
-
0 to -0.023
-
0 to -0.0139
Residual Trend COVID Indicator
-
-0.0027 to 0.0003
+
0.02 to 0.15
State Requested Percent Restriction
- -
0 to -0.81
State Drought Declaration
-0.08 to 0.01
Variables with an increasing effect on water demands included temperature, economic index, median income, and persons per household. Variables with a negative effect on water demands included precipitation, price, housing density, and water-use restrictions. Consumption is highly seasonal in the Orange County region, and the econometric model correlates well to seasonality and temperature. The single-family sector model produced the best fit among the four demand sectors.
3.3.2
Historical Model Performance
Visual inspection of the time series plots and review of the model fit parameters showed good performance across all agencies. Figure 3-2 shows an example model fit for a single retail agency in the single-family sector in gallons per account per day. The model accounts for all dips in demand.
3-8
Appendix G - 45
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