MID-PENINSULA WATER DISTRICT
Mid-Peninsula Water District’s 2025
Urban Water Management Plan
1 Kat Wuelfing, General Manager
Drew Bost, Water Resources Coordinator
June 23, 2026
MID-PENINSULA WATER DISTRICT
• District Overview
• 2025 UWMP Overview
• Demand projections
• Supply reliability
• Other planning efforts
• UWMP adoption
2 Presentation Outline
MID-PENINSULA WATER DISTRICT
• Mid-Peninsula Water
District (MPWD) Serves
potable water to:
• The City of Belmont
• Small portions of the City of San
Carlos
• Small portions of unincorporated
San Mateo County
• Serves ~31,000 people
and ~8,200 service
connections
3 Mid-Peninsula Water
District
MID-PENINSULA WATER DISTRICT
• Service connections
are comprised of:
• Residential (92%)
• Commercial, industrial,
and institutional (CII; 6.6%)
• Landscape irrigation (1%)
• Hydrants (<0.1%)
• Water demand is
comprised of:
• Residential (72%)
• CII (19%)
• Landscape irrigation (7%)
• Water Loss (1.5%)
4 Mid-Peninsula Water District
Single
Family
Residential
89.3%
Multi-Family
Residential
2.5%
Commercial
5.3%
Industrial
0.6%
Institutional
0.8%
Landscape
Irrigation
1.2%
Hydrant
0.4%
Proportion of Service Connections by
Sector
Single Family
Residential,
53%
Multi-Family
Residential,
19%
Commercial,
14%
Landscape
Irrigation,
7%
Institutional,
2.9%
Industrial,
2.0% Water Loss,
1.5%
Proportion of Water Demand
MID-PENINSULA WATER DISTRICT
• Urban Water Management Plans (UWMPs) are
required by the State for every urban water
supplier in California
• Updated every five years
• Foundational planning document
• Goal is to study and project expected and
potential water demand and supply over a 20
year horizon, and analyze the sufficiency of
availability of supply to meet demand over
different hydrologic conditions
• One of several types of supply planning that
MPWD does
• Also includes Water Shortage Contingency Plan
(WSCP) that outlines policies and actions MPWD
will implement in the event of water shortages
5 Urban Water Management Plans
Supply Demand
New
Development
Population
Shifts
Economic
Growth
Supply
Sources
Reliability
Drought
planning
2025 UWMP
MID-PENINSULA WATER DISTRICT
• MPWD will be releasing our draft UWMP
and WSCP
• Public hearing and board adoption
scheduled for July 23rd, 2026, during which
MPWD will hear all public comments and
responses to the document and the board
will vote on adoption
• Document will be published on MPWD’s
website two weeks prior (July 9th) for public
review
6 Draft 2025 UWMP and WSCP Update
MID-PENINSULA WATER DISTRICT
• As part of the UWMP process, demand
projections for the next 20 years were updated
for MPWD
• Demand modelling was conducted by Hazen and
Sawyer for the Bay Area Water Supply and
Conservation Agency (BAWSCA)
• BAWSCA is a regional entity that represents the
interests of 26 agencies that purchase water
from the San Francisco Public Utilities
Commission Regional Water System (SFPUC
RWS)
• 2025 Demand Study was conducted by Hazen
and Sawyer for all 26 BAWSCA agencies
7 2025 Demand Projections
MID-PENINSULA WATER DISTRICT
• Demand projections incorporated socioeconomic and demographic data, econometric modelling, and water conservation to forecast water demand for all water use sectors and classifications 8 2025 Demand Projections
MID-PENINSULA WATER DISTRICT
• Demand Projections were developed
with close coordination with MPWD
• Incorporates HIA Specific Plan
projected demands and land use
• Projecting 3,590 housing units
through the planning horizon (2050)
• Projecting to meet Belmont’s RHNA
needs of 1,785 units
9 2025 Demand Projections
0 200
400
600
800
1,000
1,200
1,400
Annual Forecast by Sector
SF Forecast MF Forecast CII Forecast Irrigation Forecast Recycled Forecast Other Forecast Non-Revenue Forecast Total Forecast Million Gallons (MG)
10 MID-PENINSULAWATERDISTRICT
Source: SFPUC
MID-PENINSULA WATER DISTRICT
• The 2025 UWMP projects
sufficient supply under normal
water year conditions through
2050.
11 Supply Reliability – Normal Years
Supply totals
2030 (MG) 2035 (MG) 2040 (MG) 2045 (MG) 2050 (MG)
1,040 1,099 1,183 1,262 1,280
Use totals 1,040 1,099 1,183 1,262 1,280
Surplus/(shortfall) 0 0 0 0 0
NOTES:
-The supply availability shown herein is equal to MPWD's projected SFPUC purchases.
During normal years, SFPUC supplies are available up to MPWD's ISG of 1,420 MG. See Table 4-3 and Table 6-10 for more information on MPWD's projected demands and supplies, respectively.
Normal Year Supply and Use Comparison
MID-PENINSULA WATER DISTRICT
• Dry year supply projections vary greatly
based on pending legislative actions
related to the 2018 Bay-Delta Plan
Amendment (Bay-Delta Plan)
• In 2018, the State Water Board updated
the Bay-Delta Plan to set new flow
requirements for the Lower San Joaquin
River and its tributaries aimed at protecting
native fish populations and supporting local
agricultural water needs.
• Implementation of these standards
remains subject to significant uncertainty,
as the state continues to navigate legal
challenges, ongoing scientific reviews, and
the Healthy Rivers and Landscapes (HSL)
agreement that may eventually supersede
or shape how these requirements are
enforced for water agencies.
12 Supply Reliability – Dry Years
Dry Year Supply and Use Comparison (with
Bay-Delta Plan Amendment)
2030
(MG)
2035
(MG)
2040
(MG)
2045
(MG)
2050
(MG)
Supply totals 716 736 767 797 788
Use totals 1,040 1,099 1,183 1,262 1,280
Surplus/(shortfall) (324) (363) (416) (465) (491)
2030
(MG)
2035
(MG)
2040
(MG)
2045
(MG)
2050
(MG)
Supply totals 1,040 1,099 1,183 1,262 1,280
Use totals 1,040 1,099 1,183 1,262 1,280
Surplus/(shortfall) 0 0 0 0 0
Dry Year Supply and Use Comparison (without
Bay-Delta Plan Amendment)
MID-PENINSULA WATER DISTRICT
• All large developments within HIA Specific
Plan (and elsewhere in Belmont) will
undergo a Water Supply Assessment
• UWMP may be updated if a decision is
reached by the State on the Bay-Delta Plan
before required 2030 UWMP update
• Demands are constantly monitored by
MPWD and reported monthly to the State
as well as to our Board of Directors
• MPWD meets monthly with SFPUC and the
other BAWSCA member agencies on supply
planning
13 Additional Planning Efforts
14 MID-PENINSULA WATER DISTRICT
Questions?
Drew Bost, Water Resources Coordinator
[email protected]
Kat Wuelfing, General Manager
[email protected]