Santa Barbara staff report lower baseline water demand; six scenarios to shape 2025 demand envelope

Jasmine Showers, the city’s water resources analyst, told the Water Commission on Tuesday that the city’s updated 2025 baseline water demands are “much lower than our last baseline demand projection,” a change staff attributes to lower population projections and the absence of an expected drought rebound.

The reassessment, prepared with Water Systems Consulting and Madhouse Water Management (MWM), used 2021–2024 customer water use, 2020 census data, SBCCAG growth rates, California Employment Department figures, the city’s 2035 housing element and the city’s conservation measures. Showers said the baseline projections include recycled water but exclude recycled-process sales.

Why it matters: the baseline demand feeds the city’s 5‑year planning and the 2025 Urban Water Management Plan, which triggers capital and conservation budgeting. Dakota Corey, water supply and services manager, said the baseline will be the city’s official demand for planning while a demand envelope will provide bookends for sensitivity analysis.

Staff outlined six scenarios to be modeled in a demand envelope: higher population growth (aligned with the most recent RHNA allocation), slower population growth, faster and slower job growth (a ±20% commercial-population adjustment), climate-change impacts on outdoor use and a “demand creep” scenario that anticipates a gradual return to recent high per‑capita use. Showers noted the city’s 2035 housing element projections are lower than RHNA and that ADU and multifamily growth lower persons-per-unit, moderating demand.

Consultant perspective: Michelle Madaus of MWM said statewide trends show flattened per‑capita use since COVID and drought, and that AMI (automated metering infrastructure) will allow more precise, account-level forecasting. “The more information you give me, the better the assumptions can become,” she said, describing the DSS end‑use model that breaks consumption into indoor/outdoor end uses and evaluates conservation measures at a granular level.

Questions from commissioners focused on whether water‑rate increases and contractor behaviors (which can affect rebate outcomes) are baked into scenarios; staff said rates and economic signals will be considered and that the city will seek input on the demand envelope in February and present a draft 2025 plan in April.

Next steps: staff will incorporate commission feedback into the demand envelope and return with a February presentation; the draft 2025 Urban Water Management Plan and supporting analyses are scheduled for review in April.