2025 Urban Water Management Plan

Section 6 2025 Urban Water Management Plan Water Supply Characterization City of Pleasanton Public Draft | May 2026 6-1 EKI Environment & Water, Inc. 6 WATER SUPPLY CHARACTERIZATION This section describes Pleasanton’s existing and projected water supply portfolio under normal water year conditions. The availability of the City’s water supplies under a single dry year and a drought lasting five years, as well as more frequent and severe periods of drought, are detailed in Section 7 of this UWMP. The City’s water supply portfolio consists of: • Zone 7 purchases – Pleasanton’s primary water source is treated potable supply purchased from Zone 7. As such, Zone 7’s water supplies, storage operations, and future supply projects are discussed. • Groundwater – Pleasanton typically supplements its Zone 7 purchases with groundwater pumped from City-owned wells in the Livermore Valley Groundwater Basin (Basin). The City’s groundwater supply is limited by its groundwater pumping quota (GPQ), managed by Zone 7 as the local groundwater basin manager. • Recycled water – The City augments its potable water supply with recycled water produced by DSRSD and Livermore. This section also addresses the energy intensity used to operate the City’s water distribution systems and wastewater collection system. 6.1 Purchased Water 6.1.1 Water Supply Purchases from Zone 7 Zone 7 is the Pleasanton’s sole wholesale supplier for potable water. Under the existing agreement with Zone 7, the City is limited in developing other potable water supply sources. The treated water delivered by Zone 7 complies with the Requirements for Drinking Water of the California Department of Health Services and the U.S. Environmental Protection Agency (EPA), or their successor regulatory agencies. 6.1.2 Zone 7 Water Supply Sources This section details Zone 7’s water sources and supply management. Zone 7’s water supply has two major components:  CWC §10631(b) A plan shall be adopted in accordance with this chapter that shall do all of the following: Identify and quantify, to the extent practicable, the existing and planned sources of water available to the supplier over the same five-year increments described in subdivision (a).  CWC §10631(h) A plan shall be adopted in accordance with this chapter and shall do all of the following: An urban water supplier that relies upon a wholesale agency for a source of water shall provide the wholesale agency with water use projections from that agency for that source of water in five-year increments to 20 years or as far as data is available. The wholesale agency shall provide information to the urban water supplier for inclusion in the urban water supplier’s plan that identifies and quantifies, to the extent practicable, the existing and planned sources of water as required by subdivision (b), available from the wholesale agency to the urban water supplier over the same five-year increments, and during various water-year types in accordance with subdivision (f). An urban water supplier may rely upon water supply information provided by the wholesale agency in fulfilling the plan informational requirements of subdivisions (b) and (f).