San Diego Wastewater Plant Expansion Receives $552 Million
Contractors should prepare for a multi-year construction schedule as major facility upgrades begin in San Diego.
Updated on Oct. 16, 2026 in Construction
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The U.S. IBWC has increased its primary treatment plant construction contract in San Diego to $552 million. This expansion marks a major step in the long-running effort to mitigate sewage flows from Mexico into the Tijuana River and adjacent communities.
Why it matters
The project represents a significant mobilization of resources to address a two-decade infrastructure crisis impacting regional water quality. For construction operators, the contract highlights the scale of work required to solve cross-border environmental compliance challenges.
The $552 million primary facility contract is part of a project capped at $600 million, with a 1,643-day construction schedule. Secondary treatment phases, which remain unfunded, will eventually require 10 new sedimentation tanks and seven activated sludge tanks.
The players
U.S. IBWC
The federal agency tasked with managing water treaties and infrastructure projects between the United States and Mexico.
Morley Construction
A major general contractor providing services as a project subcontractor.
Southern Contracting
An electrical and civil construction firm operating as a project subcontractor.
Technical Systems Incorporated
A systems integrator and technical partner serving as a project subcontractor.
The details
The current scope covers a new integrated headworks, a chemical system, primary sedimentation tanks, and sludge handling infrastructure, alongside a 12-kV electrical upgrade. Early work phases focus on facility painting, equipment updates, and roofing before transitioning to heavy excavation. Shoring, dewatering, and digging operations are set to commence in late October 2026 to facilitate the primary plant capacity increase.
Timeline
October 2026: Shoring, dewatering, and excavation begin.
May 2031: Substantial completion of primary treatment facilities.
Market Landscape
This project marks a significant escalation in official attempts to address the environmental crisis that has persisted for two decades. It follows the 2025 contract award to the Stantec/PCL team to initiate modernizations at the plant.
Operators in the regional construction and civil engineering supply chains should monitor for upcoming secondary treatment procurement cycles. While the primary plant expansion is underway, the future unfunded phases will eventually require significant additional material and labor inputs.
The takeaway
This project serves as a critical indicator of long-term government spending on cross-border environmental remediation. Operators should track the substantial completion target of May 2031 as a signal for the stabilization of regional wastewater demand and future infrastructure maintenance opportunities.
What happens next
The project timeline anticipates that heavy site work, including shoring, dewatering, and excavation, will begin in October 2026.
Further reading
For more on large-scale infrastructure shifts in the region, see Construction.
Source note: This article includes information reported by Engineering News-Record (ENR) magazine.
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