Recycled Water Projects

Valley Water has been using recycled water since the 1970s. For the last five decades, Valley Water has been partnering with cities and regional partners to make water reuse a possibility.


In 1975 Valley Water partnered with the city of Palo Alto to build an advanced wastewater recycled water pilot plant. The goal was to inject the recycled water into the groundwater aquifer and study changes in the water quality as it moved through the aquifer. This effort helped prevent further saltwater intrusion in groundwater aquifers. The facility was completed in 1977.
In 1977 Valley Water helped build a second wastewater reclamation plant in South County in partnership with the Gavilan Water District and city of Gilroy. The recycled water from this facility was used for irrigation and agriculture.
1991 Valley Water teamed up with the city of San José to study potable and nonpotable uses of recycled water.
In 1996 the regional South Bay Water Recycling Program was born, with the construction of the purple-colored recycled water pipeline system. The program is a partnership between the cities of San Jose, Santa Clara, Milpitas and Valley Water. By 1999, nearly 60 miles of pipeline are in place to carry recycled water throughout the region.
In 1997 Valley Water offers rebates to Sunnyvale, Santa Clara and San Jose for use of recycled water.
In 1999 Valley Water completes the South County Recycled Water Master Plan with the South County Regional Wastewater Authority, agreeing to expand use of recycled water up to 5,000 acre-feet a year by 2020.
In 2014 Valley Water and partners celebrate the grand opening of the Silicon Valley Advanced Water Purification Center in San José.
In 2017 Valley Water completes the 2.5-mile Wolfe Road Recycled Water Pipeline Project that expands recycled water opportunities in Sunnyvale and Cupertino.
In 2021 the Valley Board of Directors approved the Countywide Water Reuse Master Plan, a blueprint outlining existing and potential opportunities to expand water reuse in Santa Clara County.

Agreement with Palo Alto and Mountain View to Advance Resilient Water Reuse Programs in Santa Clara County

In December 2019, Valley Water and the cities of Palo Alto and Mountain View signed an agreement to pursue water reuse programs in Santa Clara County. The three main parts of the agreement include:

  1. Funding a local salt removal facility to be owned and operated by Palo Alto, which would provide higher quality recycled water for irrigation and industrial use.
  2. Providing wastewater from the Regional Water Quality Control Plant for a regional purification facility to be owned and operated by Valley Water to provide advanced purified water to reuse for drinking.
  3. Allow a water supply option for the cities of Palo Alto and Mountain View

As part of the agreement, Valley Water is funding $16 million out of the $20 million of the local advanced treatment facility to enhance the quality of recycled water in the region. Palo Alto is leading the design and construction of the program and is currently in the design phase. This local facility will provide up to 1.125 million gallons of purified water a day to be blended with tertiary treated water to produce high-quality recycled water. This will help increase water reuse by allowing salt-sensitive plant species, such as redwood trees, to be watered with the enhanced recycled water.

Below you can read the December 2019 Board Agenda item on the partnership agreement.

Refinery Recycled Water Exchange Project

The Refinery Recycled Water Exchange Project is a regional recycled water project with the Central Contra Costa Sanitary District and Contra Costa Water District. The project would consist of Valley Water partnering with the Sanitary District to design, build and operate a recycled water facility. The facility would provide Central Costa Water District with recycled water to for operations at two existing oil refineries. In exchange for providing recycled water for refinery operations, Valley Water would receive a share of Contra Costa Water District’s imported water from the Central Valley Project.

This project could provide up to 9,000 acre-feet* per year of water to Valley Water’s supply. However, this would increase reliance on imported water supplies. Valley Water and partners have been working on a feasibility study to evaluate the costs and benefits of this project.

*an acre-foot of water is 325,851 gallons of water, approximately the amount of water used by 10 people in a year

You can read an update on the project in the Recycled Water Committee agenda item linked below.

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