Cal Poly Pomona Reverse Osmosis Groundwater Treatment Plant

Pomona, California

Cal Poly Pomona produces and manages a portion of its own water supply and is the only university with its own reverse osmosis (RO) groundwater treatment plant (WTP) that provides the campus with a reliable local supply of drinking water. The university’s reverse osmosis brackish water treatment plant was designed to allow Cal Poly to become water independent by lessening its reliance on imported water. This $7 million WTP has the capacity to meet 100 percent of the potable water usage on campus during non-peak times. The plant is currently permitted to produce about 20,000 gallons of drinking water per hour, which amounts to more than 60 million gallons of drinking water annually. Two huge tanks, which are tucked away in elevated parts of campus, store up to 2,500,000 gallons of potable water produced by the plant.

Michael Baker served as the lead design firm responsible for the overall design, including process/mechanical, electrical/instrumentation and controls, structural, civil and design quality control. We also provided well water quality analysis, regulatory permitting, grant application assistance, cost estimating, construction management, preparation of O&M manuals and start-up assistance.

Source water for the plant is supplied by an existing groundwater well located in the Spadra Groundwater Basin, which is high in total dissolved solids; nitrates; perchlorate; and, at some locations, volatile organic compounds. The WTP is designed to treat approximately 60 percent of the raw groundwater through the reverse osmosis membrane system and bypass the remaining 40 percent, which allowed for economic sizing of the RO trains and minimization of the post treatment system.

The plant design and control system include space for a third RO train when growth and future well capacities require additional treatment capacity of up to 42,000 gallons per hour.


“By independently supplying its own potable water through the new reverse osmosis treatment plant, the campus minimizes its reliance on purchasing scarce, imported potable water from the Metropolitan Water District.”

Joel B.
Project Manager

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