Pomona Water Reclamation Plant

The Pomona Water Reclamation Plant (WRP) is located at 295 Humane Way in the city of Pomona. The plant occupies 14 acres northeast of the intersection of the Pomona (60) and Orange (57) Freeways.

The original plant, known as the Tri-City Plant, was owned by the cities of Pomona, Claremont, and La Verne. It was placed into operation in July 1926 with reuse beginning in 1927. The Sanitation Districts took over operations in 1966 and increased the plant capacity to 4 million gallons of wastewater per day.

In 1970, the plant capacity was expanded to 10 million gallons of wastewater per day with the construction of additional primary, aeration, and final sedimentation tanks. In 1977, the plant capacity increased to 15 million gallons of wastewater per day with the implementation of tertiary-level water treatment, including activated-carbon gravity filters, chlorine contact tanks, and a dechlorination system. In the early 1990s, the plant underwent a third expansion with the construction and retrofit of the activated-carbon gravity filters to deep bed anthracite filters and the addition of a third chlorine contact tank for additional disinfection capacity. To read more about the typical wastewater treatment and water reclamation process, click here.


The Pomona WRP provides primary, secondary and tertiary treatment for 15 million gallons of wastewater per day (see flow diagram below). The plant serves a population of approximately 130,000 people. Approximately 8 million gallons per day of the recycled water is used at over 190 different sites. Reuse applications include landscape irrigation of parks, schools, golf courses, greenbelts, etc.; irrigation and dust control at the Spadra Landfill; and industrial use by local manufacturers. The remainder of the recycled water is discharged into the San Jose Creek, where it is allowed to percolate into the groundwater in the unlined portions of the San Gabriel River before flowing into the ocean. To learn more about the Sanitation Districts' recycled water programs, browse the Districts' recycled water program and resources and information.