History of the District

Formation of The District

District Office circa 1962

Walnut Valley Water District Today

Upon its formation in 1952, the only potable water available for the people in this area was from local groundwater wells that were located within a very unreliable groundwater basin. In 1955, after beginning the development of the water supply system, the District provided potable water to 21 service connections with an approximate population of less than 800 in the local area.

Today, after more than six decades of service to the community, the District operates and maintains two large, imported water pipelines, 497 miles of distribution mains, 17 pump plants and 31 reservoirs with a storage capacity of 94.1 million gallons of water. The District also provides water service to over 26,500 connections in an area encompassing 17,900 acres, serving an approximate population of over 100,000 residents and businesses in six local communities.

It is quite evident that the District has grown by leaps and bounds over the last six decades, but regardless of its size, the purpose and goals of the District and its Board of Directors remain the same, to provide high quality drinking water while meeting the water supply needs of the communities we serve.

Development of Water Supplies & Distribution System

Due to the limited availability of local groundwater sources, the District is primarily dependent on surface water imported from the Colorado River and Northern California by the Metropolitan Water District of Southern California (MWD), the sole importer of water to this area, through a wholesale member agency, Three Valleys Municipal Water District (TVMWD). In 1955, the District, together with the City of Pomona and the Rowland Water District, constructed a joint pipeline (Joint Water Line) to deliver imported water to meet the water supply needs of these communities. This pipeline varies in diameter from 42 inches to 54 inches and transports potable water from MWD’s Weymouth Treatment Plant in La Verne and, when surplus water is available, from TVMWD’s Miramar Treatment Plant in Claremont to the District’s Edmund M. Biederman Terminal Storage Reservoir and Hydroelectric Facilities in Walnut.

The Joint Water Line is 7.6 miles in length and, for many years, was the District’s primary source of water until completion of the Badillo/Grand Transmission Main in 1993, which effectively doubled this area’s import water supply and provided an alternate supply route. The construction of this 5.5-mile transmission main was critical to the District since it provides access to a secondary water source, ensuring system reliability in times of catastrophic need such as fire or earthquake. The District also presently owns and operates a 150-kilowatt hydroelectric plant at its connection to the Joint Water Line. Power generated by this plant is sold to Southern California Edison.

To reduce its dependence on imported potable water, the District also operates a recycled water system for use in irrigating large, landscaped areas such as parks and school grounds, which have traditionally placed a significant demand on the District’s potable drinking water system.

The District obtains its recycled water from the County Sanitation Districts’ Pomona Water Reclamation Plant. Recycled water is the official name given to wastewater, which has undergone an extensive treatment process and is available for reuse after being tested and certified by the Department of Health Services to ensure that it is safe for irrigation purposes. The District’s recycled water system, which is separate from the potable water system, delivers an average of 763 million gallons annually of this “drought-proof” water. The recycled water supply is augmented by groundwater from the District’s recycled wells.

In 2012 the District began to explore the development of projects to diversify our water supply and further decrease our dependency on treated imported water and established a goal of developing at least 5,000 acre-feet per year of locally available water supply. In order to accomplish this goal, the District, working with the Rowland Water District through the Puente Basin Water Agency (PBWA), has explored several projects in the Main San Gabriel, Central, and 6 Basins Groundwater Basins that would allow both agencies to meet their individual water supply diversification project goals.

So far, the agencies have completed two projects that have a combined capacity of 7,000 acre-feet per year (3,500 acre-feet for each agency). In addition, the agencies are pursuing two additional projects, one currently under construction, that will yield an additional 1,500 to 3,500 acre-feet of supply annually.