Torrance Groundwater Desalter Expansion: California’s $166.5 Million Water Infrastructure Breakthrough 

At a Glance 

• Water Replenishment District (WRD) approves $166.5 million for Torrance Groundwater Desalter Expansion project, with Board approval on November 5, 2025 

• Project will expand Robert W. Goldsworthy Desalter Facility capacity to treat an additional 9 million gallons per day of drinking water by 2029 

• Advanced reverse osmosis and nano-filtration membrane technology will address seawater intrusion affecting the West Coast Groundwater Basin since early 1900s overpumping 

• McCarthy-Jacobs joint venture will lead design-build construction beginning November 2025, targeting full operational capacity by 2029 

 Southern California’s water infrastructure enters a critical expansion phase as the Water Replenishment District officially greenlit a transformative $166.5 million groundwater desalter project in Torrance on November 5, 2025. This authorization represents one of the most significant infrastructure investments in WRD’s operational history and positions the region to combat decades of coastal seawater intrusion while building long-term water resilience. 

The Torrance Groundwater Desalter Expansion will nearly double the production capacity of the existing Robert W. Goldsworthy Desalter Facility, which has served the region since its initial commissioning in 2001. The expanded facility will treat up to 9 million additional gallons of drinking water per day from the West Coast Groundwater Basin, directly serving over 88,000 residents in the City of Torrance while reducing dependence on increasingly expensive imported water sources. 

Joy Langford, WRD Board President, emphasized the project’s strategic importance during the board’s unanimous approval vote. “This approval marks a turning point for the Torrance Groundwater Desalter Expansion Project, moving us from planning to large-scale construction. It’s a testament to WRD’s vision, fiscal strength, and the power of public-private collaboration,” Langford stated in the project announcement.

Addressing a Century-Old Water Crisis 

The West Coast Groundwater Basin’s salinity crisis traces directly to groundwater extraction patterns established over a century ago. Intensive overpumping during the early 1900s lowered groundwater levels to over 100 feet below sea level, creating a pathway for seawater intrusion into freshwater aquifers. This geological consequence has persisted through multiple decades, rendering significant portions of the basin’s groundwater unsuitable for municipal use without advanced treatment. 

The expanded desalter will extract brackish and saline groundwater from the West Coast Basin, removing that salty water while simultaneously creating storage capacity for fresh and recycled water needed during future drought years. This dual benefit transforms the project from a simple desalination expansion into a comprehensive groundwater management strategy aligned with California’s broader water resilience objectives. 

RO Katherman, WRD Director, highlighted the project’s multifaceted benefits. “This project has been years in the making, and today’s approval brings us one step closer to restoring the basin’s brackish groundwater into a usable resource. It also provides long-term rate stability for our residents and reduces our reliance on increasingly costly imported water.” 

Advanced Technology Deployment 

The McCarthy-Jacobs joint venture was selected to design and construct the facility using a progressive design-build delivery model that prioritizes cost control and schedule efficiency. The expanded desalter will utilize reverse osmosis membrane technology combined with nano-filtration systems to remove dissolved salts from extracted groundwater, producing potable water meeting state and federal standards. 

According to project specifications, the facility will incorporate one of the world’s largest biological pre-treatment systems, enabling the expanded desalter to handle complex water chemistry variations across the West Coast Basin. The reverse osmosis process, paired with advanced pretreatment and post-treatment systems, delivers high-quality drinking water while addressing the specific salinity challenges present in Southern California’s coastal aquifers. 

Katus Watson, Jacobs Senior Vice President, explained the project’s engineering approach during contract award announcements. “The progressive design-build delivery model allows us to work collaboratively to minimize cost, reduce risk, streamline construction and improve schedule performance to fast track the completion of this state-of-the-art facility that will provide a sustainable drinking water supply for the near term and well into the future.” 

McCarthy’s Water Group Vice President Sagrado Sparks added industry perspective on California’s water infrastructure imperative. “As water resources in the West are increasingly strained, advanced water treatment technologies are providing excellent solutions for communities like Torrance to ensure a sustainable and resilient water supply. Projects like this are proactively addressing water supply issues through proven technologies and continue to position California as a leader in protecting and preserving its fragile drinking water supply.” 

Project Scope and Timeline 

Beyond the desalter facility expansion, the project scope includes construction of four new groundwater extraction wells and associated raw water pipelines designed to support the enhanced treatment capacity. WRD has secured partial project funding through the U.S. Department of the Interior’s Bureau of Reclamation WaterSMART grant program, which awarded $25 million in 2024 as the largest desalination project grant in that funding round. 

The comprehensive funding package combines WRD’s Capital Improvement Program, state and federal grants, a state low-interest loan, and a projected 2027 bond issuance under WRD’s Brackish Groundwater Reclamation Program scheduled for first quarter 2027. Construction mobilization begins in November 2025, with completion anticipated in 2029 and full operational capacity targeted for 2029. 

Final Thoughts 

The Torrance Groundwater Desalter Expansion represents California’s ongoing commitment to developing local, drought-resistant water supplies while addressing historical environmental conditions created by past groundwater management practices. As climate change intensifies regional water stress and sea level rise compounds coastal aquifer challenges, advanced desalination projects anchored in proven technologies continue to serve as critical infrastructure components for Southern California’s long-term water security.