Oliver P. Roemer Expansion and Upgrade Project

Concept Drawing of the Oliver P. Roemer Watr Filtration Facility

West Valley Water District (District) proudly serves the Southern California communities of Rialto, Fontana, Colton, Bloomington, Jurupa Valley and unincorporated areas San Bernardino County. Over our agency’s many decades, our mission has always remained the same: to provide customers with safe, high quality, and reliable water service at a reasonable rate and in a sustainable manner.

To that end, the District is expanding the treatment capacity at the Oliver P. Roemer Water Filtration Facility to 21.6 million gallons per day (MGD) through an ambitious capital improvement project. The Project is being implemented to replace aging infrastructure, meet rising peak summer demands, provide existing users with a reliable water supply, meet projected demands due to infill and growth and to responsibly manage regional groundwater basins. With the implementation of the Project, the District is seeking to implement a conjunctive use strategy which is critical for the long-term, sustainable water management for the region.

The Oliver P. Roemer Water Filtration Facility is a surface water treatment plant that treats local surface flows from Lytle Creek and imported water delivered through the State Water Project pipeline. This Project will expand treatment capacity at the facility by 7.2 MGD and allow the District to maximize the use of surface water supplies when available and supplement this supply with local groundwater to meet water demands.




Enhances the existing water filtration facility to help ensure long-term dependability; Replaces aging infrastructure, bring the existing facilities and equipment up to today’s standards; Expands treatment capacity from 14.4 Million Gallons per Day (MGD) to 21.6 MGD which provides operational flexibility; Balances the use of groundwater, local surface water and imported water supply.


In 1995, West Valley Water District and the City of Rialto jointly constructed the original 7.2 Million Gallons Per Day (MGD) Oliver P. Roemer Water Filtration Facility to treat their Lytle Creek surface water rights for potable water use. 

In 1998, the District expanded the treatment capacity at the facility from 7.2 MGD to 9.6 MGD to allow the District to treat both Lytle Creek surface water and purchased State Water Project water.

In 2006 treatment capacity at the facility was expanded again from 9.6 MGD to 14.4 MGD by installing two new contact adsorption clarification package treatment units.  This upgrade expanded the treatment process capability of the plant to achieve both turbidity removal and total organic carbon reduction by installing pretreatment facilities consisting of chemical feed, flocculation and sedimentation facilities; installation of new ultraviolet light (UV) disinfection equipment; six (6) Granular Activated Carbon (GAC) removal vessels, construction of a raw water pumping station; influent blending pond; and sludge ponds.

In the summer of 2009, a new 36-inch raw water pipeline, which replaced an aging 12-inch pipeline was constructed which increased the District’s ability to take up to 20 MGD of SWP water.  In 2016 four (4) GAC vessels were added to the system to aid in the removal of total organic carbon.

With this new expansion project, treatment capacity at the facility will be increased from it’s current 14.4 MGD to 21.6 MGD by installing three (3) Trident packaged Contact Adsorption Clarifier (CAC) and Filter units.  A new influent pump station will supply water to the new Filter units and a new effluent pump station will pump this additional capacity to an existing off site storage reservoir through a 30-inch treated water pipeline in W. Via Bello Ave.  Three (3) inline UV Reactors and GAC pumps will replace existing units to meet the increased needs from the added facility capacity.  New recovery pond pumps and new piping will provide operators the flexibility to pump backwash and filter to waste water to either the existing pretreatment facilities or the existing sludge ponds.  A pre-engineered metal Filter Building will be constructed directly adjacent to the existing Filter Building to house the three new CAC/Filters and includes room for future CAC/Filters.  A new Programable Logic Controller (PLC) room, laboratory and SCADA room will be constructed to operate the entire facility.  This system integrates existing equipment and facility operations with new equipment and is a single source of communication and control of the facility.

August 2023 Project Update

On site, PCL Construction has been busy installing a new 12-inch backwash pipeline, electrical conduits and excavating for the future Effluent Pump Station. Piles were drilled to house the I-beams that will be used to support the shoring of the Effluent Pump Station.  Pipe and other materials are arriving on-site for anticipation of their future installation.  As this project is being delivered through a Design Build process, 90% designs of the various disciplines where finalized.






Project Highlights:  



Upgrades and Expansion of the Oliver P. Roemer Water Filtration Facility began in July 2023 and is expected to be completed in the Spring of 2025.

The major phases of construction to occur over the course of the project include:

  • Demolition at the existing site
  • Earthwork excavation and shoring
  • Concrete construction
  • Influent and Effluent Pump Station construction
  • Filter Building construction
  • Onsite pipeline construction
  • Offsite pipeline construction
  • Site paving


As the lead agency, the District followed the California Environmental Quality Act (CEQA) process and approved an Initial Study/Mitigated Negative Declaration (IS/MND) in September 2021. Included in the IS/MND is the Mitigation Monitoring and Reporting Program (MMRP) that was developed to ensure potential impacts will be mitigated to a less than significant level during construction.

The Initial Study/MND and the MMRP are available for download and review at the following document links:



What is the Project?

The largest capital project that West Valley Water District (District) has undertaken, the Oliver P. Roemer Water Filtration Facility Upgrade and Expansion Project.  This project expands water treatment capacity at the existing treatment facility by 7.2 million gallons per day and upgrades existing infrastructure.


Where is the Project?

The project is located at the existing Oliver P. Roemer Water Filtration Facility, 3010 N. Cedar Ave. in the City of Rialto.  More specifically northern Rialto just off of Riverside Ave. between Linden Ave. and Cedar Ave.


What are the Project Elements?

The main elements of the 7.2MGD Oliver P. Roemer Water Filtration Facility Upgrade and Expansion Project include:

Influent & Effluent Pump Stations Filter Building housing 3 New Trident Filtration Units New PLC Room, Laboratory & SCADA Control Room Electrical and Mechanical Upgrades 3 Ultraviolet Disinfection Reactors Upgrade UV Recovery & GAC Influent Pumps 30inch Treated Water Pipeline Replacement of Aging Infrastructure at the facility New and Upgraded PLCs, SCADA and System Security Emergency Generator


How does the Project Benefit the Community?

The project enhances various elements at the existing Oliver P. Roemer Water Filtration Facility which will help to ensure long-term dependability.  It replaces aging infrastructure, bringing the existing facilities and equipment up to today’s standards and expands treatment capacity from 14.4 MGD to 21.6MGD which provides operational flexibility.  The project will allow the District to balance the use of groundwater, local surface water and imported water supplies based on availability, water quality, treatment costs and water demands.


Who is Building the Project?

The District awarded a design build contract to PCL Construction for the construction and design of the project.  PCL Construction has teamed up with Stantec to provide engineering services.  In addition, the District awarded a contract to GHD for construction management of the project.


How is the water treated?

The Oliver P. Roemer Water Filtration Facility we use a series of water treatment steps that include coagulation, flocculation, sedimentation, filtration, and disinfection.


Design Build Contractor:

PCL Construction


Design Build Design Engineers:



Project/Construction Management:

GHD – A company offering engineering, architecture, environmental & construction services

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