Sweetwater Authority advances South Bay desal plant with well siting contract

Sweetwater Authority advances South Bay desal plant with well siting contractThe California utility awarded a $156,124 contract to Geoscience Support Services to identify locations for five new brackish groundwater wells to feed a proposed 4 MGD desalination facility.

Geoscience will identify sites for five raw water supply wells, each expected to produce 1,000 gallons per minute from the San Diego Formation.

The scope includes designing and supporting the construction of an 800- to 900-foot-deep zone sample well at the highest-ranked site to obtain water quality and quantity data.

The proposed South Bay Brackish Groundwater Desalination Facility could yield approximately 4,480 acre-feet per year, reducing the utility's reliance on imported water.

The board approved the contract with a $16,000 contingency, funded through the FY 2025-26 engineering consulting budget.

Sweetwater Authority has taken a key step toward expanding its local water supply by approving a well siting study for its proposed South Bay Brackish Groundwater Desalination Facility in southern Chula Vista, California. During a May 15, 2026 special meeting, the utility's Governing Board awarded a $156,124 professional services agreement to Geoscience Support Services, Inc. to identify suitable locations for five new raw water supply wells. The board also authorized a $16,000 contingency fund for the work. The proposed 4 million gallon per day (MGD) desalination facility is expected to produce approximately 4,480 acre-feet per year, representing more than half of the current maximum yield of the utility's existing Richard A. Reynolds Desalination Facility. The project is part of a broader strategic effort to reduce the authority's reliance on costly imported water. Under the approved contract, Geoscience will identify sites for five wells expected to draw from the San Diego Formation, with each well targeted to produce approximately 1,000 gallons per minute. As part of the study, the consultant will also develop a plan and technical specifications to construct a zone sample well—anticipated to be 800 to 900 feet deep—at the highest-ranked site. This sample well will be used to gather critical water quality and aquifer data to inform the final well designs. The contract was awarded following a competitive request for proposals process that drew seven submissions. According to a staff presentation, Geoscience was selected as the highest-ranked proposer due to its strong local experience with the San Diego Formation, positive past performance with the utility, and a detailed GIS-based site suitability analysis approach. Initial funding for the study will be drawn from the authority's fiscal year 2025-26 engineering consulting budget, while the proposed FY 2026-27 budget includes a $500,000 request to cover the remainder of the initial efforts and subsequent well drilling. The siting study will proceed in parallel with the South Bay Desalination Feasibility Study.