W.A. Rasic Construction has received a major subcontract worth $85 million to help build the Joint Water Pollution Control Plant (JWPCP) Effluent Outfall Tunnel, a massive infrastructure project designed to modernize and secure wastewater discharge for millions in Los Angeles County.
The W.A. Rasic Construction, the California-based contractor was contracted by Dragados USA, the project’s lead contractor, to lay down 12-foot diameter segments of pipeline—a main part of the tunnel system carrying treated effluent from Carson’s plant to Rancho Palos Verdes’ Royal Palms Beach. The new connections will couple the existing JWPCP force main with the vertical shaft of the tunnel, improving flow capacity, seismic strength, and long-term operational resilience.
W.A. Rasic said it is proud to bring its expertise in deep excavation and large-diameter pipeline work to a project of this scale and complexity, underscoring a commitment to safety, innovation, and skilled local employment.
The JWPCP Effluent Outfall Tunnel is the most challenging tunneling project in North America currently under construction. The tunnel will be built 450 feet below grade for a number of miles for $630 million. It will be a critical improvement of LA County’s deteriorating wastewater outfall system.
Commissioned by the Sanitation Districts of Los Angeles County, the tunnel will replace two lines built in 1937 and 1958. Upon completion, it will supply vital redundancy, reduce environmental risks, and allow the county to meet modern climate adaptation demands.
Major technical achievements
One of the project’s major technical achievements is post-tensioned concrete segmental lining— a first for tunnel construction in North America. The innovative method involves higher structural strength in seismically active regions and has been used only a few times globally.
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Project Milestones and Delivery Timeline
The tunnel and associated facility construction was contracted to Dragados USA under a single contract in January 2019 with formal Notice to Proceed in April 2019. The project is still on track for completion in October 2026 according to the contractor, though there is complexity in excavating the tunnel across different geologies and fault lines.
A 21-foot diameter, on-site-assembled, German-built Tunnel Boring Machine (TBM) is boring through conditions of soft soil to hard rock with faulting that traverses beneath the Palos Verdes Fault Zone. Ground pressures along the route vary from 1 to 9 bar and are among the project’s engineering challenges.
Project Owner and Design Team
The Sanitation Districts of Los Angeles County are building the tunnel. This 24-member group of independent special districts supplies wastewater and solid waste services to more than 5.6 million residents. Seventeen of the districts belong to the Joint Outfall System (JOS)—a regional network of linked wastewater infrastructure.
Parsons is the project’s lead designer, overseeing the creation of an outfall system that not only meets existing regulatory and environmental standards but also meets the demands of future climatic events.
Local Impact
In addition to its engineering significance, the project will create hundreds of constructions and skilled trade jobs for the Los Angeles community. The new role of W.A. Rasic follows announcement by the company and reflects the firm’s established proficiency in offering advanced civil infrastructure across California.
JWPCP Effluent Outfall Tunnel: Project Factsheet
Project Overview
Location: Carson to Rancho Palos Verdes, Los Angeles County, CA
Total Budget: $630 million
Completion: October 2026
Owner: Sanitation Districts of Los Angeles County
Key Technical Features
Tunnel Diameter: Bored by 21-foot diameter German-manufactured TBM
Depth: 450 feet underground
Advanced Lining: First North American use of post-tensioned concrete segmental lining
Seismic Design: Enhanced structural strength for seismic zone conditions
Ground Conditions: Varied geology from soft soils to hard rock, crossing Palos Verdes Fault Zone
Operating Pressures: 1-9 bar range
Major Contracts
Primary Contractor: Dragados USA
Contract awarded: January 2019
Notice to Proceed: April 2019
Major Subcontractor: W.A. Rasic Construction
Subcontract value: $85 million
Scope: Installation of 12-foot diameter pipeline segments connecting existing JWPCP force main to tunnel vertical shaft
Design & Engineering
Lead Designer: Parsons
Project Significance
Infrastructure Replacement: Modernizes outfall systems originally built in 1937 and 1958
Redundancy: Provides critical backup capacity for regional wastewater discharge
Environmental Protection: Reduces environmental risks and supports climate adaptation goals
Economic Impact: Hundreds of constructions and skilled trade jobs in LA region
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