RES 231414 - Laserfiche WebLink

C-44 | City of Pleasanton Housing Constraints development of as many as 26 locations preliminarily studied as potential housing sites (versus the 19 re-zone sites ultimately selected for inclusion in the Housing Element), and assuming new housing would be in addition to, rather than replace, any existing non-residential uses on site. As such, the minor exceedance of demand compared to the UWMP was determined not to be significant. However, the WSA noted that it is possible that additional water supply sources may be necessary to accommodate the Housing Element Update combined with additional growth, under the conservative demand forecast. Zone 7 has committed to work to increase water supply sources for the City and surrounding areas to account for increasing population and climate changes. Not reflected in the 2020 UWMP, but acknowledged in the WSA for the Housing Element update, are supply deficiencies due to the recently-emerging issue of contamination by per- and polyfluoroalkyl substances (PFAS, chemicals that can contaminate drinking water supplies) in local groundwater supplies. The City’s water supply comes from two sources: approximately 80 percent is supplied by the Zone 7 Water Agency (Zone 7), while the remaining 20 percent comes from three City owned groundwater wells: Wells 5, 6, and 8. Well 8 was placed in “Standby Service” with the Division of Drinking Water (DDW) in June 2019 due to PFAS concentrations being significantly above response levels at the time of its issuance. The well has not operated since June 2019. Well 5 and 6 are still “In Service” with DDW but have not operated since November 2022. This is a precautionary decision made based on test results being near response levels. When regulatory maximum contaminant levels (MCLs) are established (estimated to occur late 2023 / early 2024), the City anticipates all three wells will be above the MCLs. A supply deficiency would remain until the groundwater supply wells have PFAS treatment added or alternative water supplies are found. As a result, the City is actively exploring several alternative water supply options while the PFAS contamination is being addressed. In September 2020, the City began considering a PFAS Treatment and Wells Rehabilitation Project to address PFAS contamination and extend the life of the existing groundwater supply by 30 years. This project would rehabilitate/replace existing well facilities and construct a Centralized Treatment Facility for disinfection and PFAS treatment of groundwater before distribution. The preliminary cost estimate of the project is $46 million. Given project cost and other considerations, in September 2022, the City Council authorized staff to proceed with performing a Water Supply Alternatives Study and put the PFAS Treatment and Wells Rehabilitation Project on hold. As of April 2023, the Alternatives Study is well underway, and is evaluating the relative costs and feasibility of alternatives such as: • Proceeding with the well rehabilitation project as previously scoped or with a modified scope; • Constructing new City wells outside the PFAS plume; • Zone 7 pumping City’s groundwater allotment on its behalf using newly installed infrastructure;