DATE:
May 26, 2026
CATEGORY:
Public Hearing
DEPT.:
Public Works
TITLE: 5-Year Update to the Urban Water
Management Plan and Water Shortage
Contingency Plan
RECOMMENDATION
Hold a public hearing to accept and consider public comments on the: Draft 202 5 Urban Water Management Plan and Water Shortage Contingency Plan as required by California Water Code Section 10642.
BACKGROUND
The California Water Code requires urban water suppliers to prepare an Urban Water Management Plan (UWMP) to analyze available water supply during normal and dry years, compared to current and projected water demand. UWMP updates are required every five years.
The City of Mountain View’s 2020 UWMP was adopted in 2021, and submittal of the 2025 UWMP is due to the California Department of Water Resources by July 1 , 2026 in order to maintain eligibility for State water grant funding.
The UWMP is a link between land use planning and water supply planning, developed to evaluate if sufficient water is available to meet the needs of Mountain View’s existing and future water customers. This UWMP update also includes an update to a Water Shortage Contingency Plan as required by State law. In preparing this UWMP update, staff worked collaboratively with the City’s wholesale water suppliers to exchange necessary information. Notice of the preparation and adoption process was posted in local newspapers and emailed to key neighborhood and business liaisons, local water agencies, and the County of Santa Clara.
ANALYSIS
Mountain View’s 202 5 UWMP provides an analysis of historical, current, and projected water supply and demand. The 2025 UWMP also includes details about the City’s climate, service area, potable water supply, recycled water program, water conservation program, supply reliability during normal and drought years, and actions to be taken in the event of a water shortage emergency. A summary of each item discussed in the UWMP is provided in the Executive Summary (Attachment 1). The 2025 UWMP document is posted o nline at:
mountainview.gov/uwmp.
5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
Water Demand and Supply
Mountain View’s municipal water system serves the majority of businesses and residents within the City limits. A small number of customers are served by the California Water Service Company, and not by the City. Future water demand projections for the water service area were developed based on the approved General Plan and affiliated plans and policies, over a planning horizon of 25 years. Consistent with the City’s current adopted land use plans and policies, this UWMP evaluates collective growth up to 148,200 residents by 20 50 - a 76% increase from the current level (Figure 1).
Figure 1: Historical and Projected Water Service Area Population
Mountain View purchases the majority of the City’s drinking water from the San Francisco Public Utilities Commission (SFPUC), sourced primarily from the Tuolumne River and captured in the Hetch Hetchy Reservoir in Yosemite National Park. Drinking water is also purchased from the Santa Clara Valley Water District (Valley Water) and pumped from local groundwater wells.
Recycled water from the Regional Water Quality Control Plant located in the City of Palo Alto is also used to meet some irrigation, industrial, and toilet flushing demands in the North Bayshore Area. Mountain View’s water demand is projected to increase by 32% over the next 25 years, if all approved development (with an estimated population increase of 76%) is completed within this horizon (Figure 2). Future demand projections reflect a continued trend of reduced per capita water use over time.
5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
Figure 2: Historical and Projected Water Demand
The percentage of each supply used to meet Mountain View’s water demand changes year to year based on many factors, such as supply availability and the magnitude and geographical distribution of customer demand. Current water use is comprised of 84% SFPUC, 8% Valley Water, 6% recycled water, and 2% groundwater. Figure 3 shows the City’s historical and projected water supply production by source.
5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
Figure 3: Water Production by Source
Water Supply Reliability
One major component of a UWMP is the water service reliability assessment, which evaluates the availability of Mountain View’s water supplies during normal and dry years. Several new water supply reliability considerations have arisen over the last decade, most notably the State Water Quality Control Board’s amendment to the Water Quality Control Plan for the San Francisco Bay / Sacramento-San Joaquin Delta Estuary. This plan establishes water quality objectives to maintain the health of the Bay Delta ecosystem. One main component of the Bay - Delta Plan Amendment includes increasing water flows in tributaries of the San Joaquin River, including the Tuolumne River. Several agencies are challenging the Bay -Delta Plan Amendment, and the State Board is negotiating with water rights holders to find a middle ground. At this time, the final outcome of the Bay-Delta Plan Amendment remains uncertain.
In preparation for this UWMP update, SFPUC and Valley Water evaluated supply availability and the ability to meet systemwide demand through 20 50. Valley Water projects supply reductions of up to 9% during some multiple year droughts. SFPUC projects that implementation of the Bay- Delta Plan Amendment would result in systemwide water shortages during dry years. Cumulative impacts to Mountain View’s SFPUC supply are estimated to be up to 48% reduction (due to 43% system-wide cutbacks) . To address the projected shortfalls and meet their adopted level of service goals, SFPUC is evaluating alternative supply options, including potable water reuse. If the
5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
Bay-Delta Plan Amendment is not implemented as adopted, SFPUC projects sufficient water to meet system-wide demands during all years (normal and dry) through 2050.
Based on reliability information provided by both SFPUC and Valley Water, Mountain View expects to be able to meet projected water demand during all normal years through 20 50, but projects cumulative dry -year supply shortfalls of up to 20% (with implementation of the Bay- Delta Plan Amendment). Reductions to the City’s imported water supplies would be replaced by increasing groundwater production and implementing customer demand reduction measures.
Water Shortage Contingency Plan
Mountain View’s Water Shortage Contingency Plan (Chapter 8 of the UWMP) serves as a flexible framework of planned response measures to address water supply shortages. The plan describes demand reduction strategies to meet various stages of shortages, including up to 10%, 11 to 25%, 26 to 40%, and greater than 40%. Each stage includes a set of actions that become progressively more stringent as the shortage condition escalates. All of the stages are designed to provide adequate water to protect public health and safety and satisfy the City’s fire protection needs.
No significant modifications have been made to the Water Shortage Plan as part of this UWMP update, but State law requires a public hearing be held specifically on the Water Shortage Plan, in addition to the UWMP.
Next Steps
Following this public hearing, staff will return to the City Council for adoption of the resolutions approving the 202 5 UWMP and Water Shortage Contingency Plan on June 23, 202 6. Staff will submit the final report to the California Department of Water Resources, the State Library, and the County of Santa Clara. The adopted 2025 UWMP will also be posted on the City’s website and be available in the Mountain View Library.
FISCAL IMPACT
None.
LEVINE ACT
California Government Code Section 84308 (also known as the Levine Act) prohibits city officials from participating in any proceeding involving a “license, permit, or other entitlement for use” if the official has received a campaign contribution exceeding $500 from a party, participant, or agent of a party or participant within the last 12 months. The Levine Act is intended to prevent financial influence on decisions that affect specific, identifiable persons or participants. For more 5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
information see the Fair Political Practices Commission website: www.fppc.ca.gov/learn/pay-to- play-limits-and-prohibitions.html
Please see below for information about whether the recommended action for this agenda item is subject to or exempt from the Levine Act.
EXEMPT FROM THE LEVINE ACT
☒ General policy and legislative actions
CONCLUSION
Mountain View updates the City’s UWMP every five years to evaluate the City’s ability to meet the City’s water needs over the next 25 years. This UWMP considers water demand associated with current customers, as well as new customers arising from implement ation of currently adopted land use plans and policies . This growth is projected to increase water use b y 3 2% between 202 5 and 20 50. Mountain View will meet these water needs through continued implementation of water conservation measures and use of the City’s four water supplies: SFPUC, Valley Water, groundwater, and recycled water. Mountain View continues to collaborate with wholesale suppliers and other regional partners to sustainably manage water supplies and meet the City’s water needs now and in the future.
ALTERNATIVES
1. Provide changes to the Draft 2025 UWMP or Water Shortage Contingency Plan.
2. Seek additional research or provide other direction.
5-Year Update to the Urban Water Management Plan and
Water Shortage Contingency Plan
May 26, 2026
PUBLIC NOTICING
Agenda posting and publication in the Daily Post . Notifications were also emailed to neighborhood and business liaisons, local water agencies, and the County of Santa Clara.
Prepared by:
Elizabeth Flegel
Water Resources Manager
Reviewed by:
Lisa Au
Assistant Public Works Director
Approved by:
Jennifer Ng
Public Works Director
Kimbra McCarthy
City Manager
Attachment: 1. Urban Water Management Plan Executive Summary