Rio Vista Water Treatment Plant Expansion

Preparing for the Next Two Decades—and Beyond

The Castaic Lake Water Agency had to update its Rio Vista water treatment plant to meet demand in the Santa Clarita valley. With Harris overseeing the expansion, the plant now handles more than twice its previous capacity and does so more efficiently—ensuring its viability for the next two decades.

But team members also planned farther ahead, designing and incorporating elements that will enable the plant to more than double its capacity again after 2034.

Harris provided construction management services for the wholesale water agency, including:

  • Implementing pre-construction and ongoing biddability/constructability reviews
  • Mitigating impacts on the job site and adjacent environment
  • Conducting community outreach

Using efficient treatment processes, the team was able to repurpose systems for operational flexibility, boost infrastructure lifetimes and improve safety at the site. Upgrades to the switchgear and chemical storage and delivery systems and a new fuel storage tank, raw water pumps and more were all part of the plant’s revamping.

To meet the tight deadlines and technical challenges, Harris consistently found ways to refine or accelerate construction activities. Harris' effective project control systems held the cost of change orders to less than five percent of the contract price.

Core Elements

The $37 million project improvements included:

  • Conversion of a raw water pipeline to an ozone pipeline contactor
  • Construction of a building with six clarifiers and six filters
  • Construction of a chlorine storage and feed system designed for twice the post-expansion capacity
  • Installation of pump stations for plant water and a sludge-thickener tank
  • Construction and modification of washwater recovery basins
  • Installation and modification of electrical controls, with a master programmable logic controller to support future capacity

Beyond the Blueprints

Building for the future while operating in the present calls for organized and efficient processes—especially with high-visibility services like water treatment.

Unforeseen technical difficulties and new standards posed challenges, but the team was dedicated to making the facility a world-class operation. Harris’s coordination and communication on tight scheduling, complicated logistics and complex issue resolution were vital to the project's success.

Meet the Team

Vern Phillips, PE

Vern Phillips, PE

Principal Engineer / Engineering


Castaic Lake Water Agency (CLWA)


Santa Clarita, CA


Water Reuse
Public Works


Construction Management




2012 APWA, Public Works Project of the Year