Draft 2025 Urban Water Management Plan

2025 Orange County Water Demand Projection Model

Data Category

Variable

Source

Assumptions

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

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

The baseline scenario assumes no active conservation measures.

Residential use (single-family and multifamily) accounts for approximately 60% of total Orange County demand and is expected to drive changes to the total demand forecast, despite CII use increasing as jobs increase. Figure ES-1 indicates that multifamily growth is expected to outpace single-family growth out to 2050.

800,000

800,000

700,000

700,000

600,000

600,000

500,000

500,000

January 2025 – January 2030

400,000

400,000

300,000

300,000

200,000

200,000

100,000

100,000

0

0

Historical

Projected

Historical

Projected

Figure ES-1: Single-family and Multifamily Growth

Additionally, Figure ES-2 shows that average persons per household is expected to decrease for both residential sectors while household density increases.

9

Appendix G - 14

Powered by