Draft 2025 Urban Water Management Plan

2025 Orange County Water Demand Projection Model

2. Historical Data Collection and Review Demand model development requires a robust historical data set comprised of water consumption, driver units (billing accounts), and explanatory variables to explain historical changes in water use. The explanatory variables used in the models reflect both data availability and Hazen’s nationwide demand modeling experience, which has focused heavily on variables that affect long term demand in California. Table 2-1 provides a summary of the data used to develop the econometric models.

Table 2-1: Summary of Historical Data Collected for Model Development

Data Category

Dataset

Data Source(s)

Historical billed consumption and accounts For SF, MF, and Irr uses: Single- family, and multifamily, commercial, and irrigation accounts, Dedicated Irrigation (potable, recycled & raw water)

Retailer billing records (2010 – 2024)

Water Use

Retailer billing records (2010 – 2024)

Driver Units

For CII uses: CII Sectoral employment

US Census

Observed weather (monthly precipitation, monthly maximum temperature)

Parameter-elevation Regressions on Independent Slopes Model (PRISM) Retail agency provided (2010 – 2024) State Water Resources Control Board Federal Reserve Bank of St. Louis Real Gross Domestic Product: All Industries in Orange County, CA US Census American Community Survey (ACS) US Census American Community Survey (ACS), California State University Fullerton Center for Demographics Research (CDR), Southern California Association of Governments (SCAG) land use data US Census LODES, Center for Demographics Research (CDR) Analysis of trend indicators and MWDOC/FLUME insight Assumed active from March 2020 – May 2023

Water Price

Drought Restrictions

Gross Domestic Product (GDP)

Median income

Explanatory Variables

Housing density

Persons Per Household

Relative sectoral economic activity

Passive Efficiency Estimates

COVID Binary Indicator

The following sections provide a detailed description of each dataset summarized in Table 2-1. Data sources documented in this section are limited to historical datasets; a review of datasets describing projected future conditions and assumptions are documented in Section 4 .

2-1

Appendix G - 20

Powered by