This project began operating in August 2009 to slow down the buildup of salts and minerals in the groundwater basin in order to:
- protect the basin's long-term use
- facilitate the use of recycled water for irrigation purposes, thereby enhancing the Valley's overall water-supply reliability, and
- soften some of the groundwater supplies delivered primarily to the western side of Zone 7's service area (the City of Pleasanton and the Dublin San Ramon Services District).
To view an article that appeared in the November/December 2012 edition of Water System Operator magazine, click here.
Groundwater is pumped to the facility for removal of minerals, such as calcium and magnesium, which, while not harmful to health, can leave buildup on plumbing fixtures.
- For a fact sheet on water hardness, click here.
- For a fact sheet about the plant, click here
For a press release about the plant, click here
Several dozen people attended an opening celebration at the Mocho Groundwater Demineralization Plant on September 23, 2009, including water retailer representatives and several neighbors of the plant.
How it Works
The Mocho Groundwater Deminerization Plant uses reverse-osmosis (RO) membrane technology to treat up to 7.7 million gallons of groundwater a day pumped from a series of nearby existing Zone 7 wells. After the salt concentrate is removed, about 6.1 millions gallons per day of treated water is available for blending with other supplies prior to delivery to retailers. Zone 7 has partnered with the Dublin San Ramon Services District (DSRSD), a water retailer and the wastewater services provider in the western portion of the Valley, to discharge up to 1.6 million gallons per day of salt concentrate to the San Francisco Bay via the DSRSD system and, ultimately, the Livermore Amador Valley Water Management Agency (LAVWMA) export pipeline. For environmental documentation, click here.
- Completion: August 2009
Cost: $35.6 million, funded by water rates, connection fees on new development and a $740,000 Proposition 50 state grant
A second plant of comparable size and cost, funded entirely by new development, is planned for the future.