Your WaterFlood and Stream ManagementWatershed and Environment

Andrea Olson of Assemblywoman Joan Buchanan's office (left) presents commendation for solar project to Zone 7 board President John Greci (center) and General Manager Jill Dueig (right)

Zone 7 has taken big steps in both reducing energy costs and helping the environment.

In 2011, the Agency completed a solar power installation at its Del Valle Water Treatment Plant. More recently, in 2013, it worked to increase its alternative power and renewable energy use portfolio through a Power and Water Resources Pooling Authority (PWRPA) project at the Patterson Pass Water Treatment Plant. The next planned PWRPA project is at the Mocho Groundwater Demineralization Plant and two nearby wells.

"This is a win-win for our water ratepayers and for the environment," Zone 7 board President John Greci said during a solar project open house celebration on June 22, 2011.

In a partnership between Zone 7 and Borrego Solar Systems Inc., Borrego -- a leading designer and installer of grid-tied solar electric power systems -- designed and built, and now operates and maintains, the 348-kilowatt photovolatic system at its own expense. Zone 7 will buy all of the electricity the facility produces at a fixed rate. 

The solar panels will produce about a third of the energy Zone 7 uses in water-treatment and other operations at the Del Valle plant. Zone 7's estimated reduction in energy costs is expected to exceed $800,000 over the 20-year term of the agreement. In addition, by reducing reliance on conventional power plants that burn fossil fuels, the project will cut annual greenhouse gas emissions that contribute to global climate change.

For a fact sheet on the facility, click here.


To view Zone 7's main Watershed & Environment page, click here.

mocho2This 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.



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. 



 ro-graphic.jpgHow 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.




  • 10/22/12 Zone 7 Board Holds the Line on Water Rates
  • 6/1/12 DSRSD, Zone 7 Honor Former Director, Jim Kohnen
  • 5/4/12 May 10 Workshop on SB 1337 Canceled


  • 10/20/11 Board Approves 5% Increase in Wholesale Water Rates
  • 6/27/11 Zone 7 Goes Solar
  • 5/20/11 Board Lauds Science Fair Winners, Businesses for Conservation Efforts


  • 10/22/10 Board Approves 2.5 Percent Water Rate Increase 
  • 5/24/10 Board Lauds Science Fair Winners, Businesses for Conservation Efforts
  • 4/21/10 Zone 7 Board Foregoes Increased Pay
  • 4/21/10 Zone 7 Board Awards Grant to Facilitate Stream Improvements
  • 3/16/10 Free Water-Wise Gardening & Water Efficiency Workshops


  • 10/21/09 Wholesale Water Rates to Increase
  • 8/12/09 New Facility Reduces Groundwater Hardness
  • 6/26/09 Zone 7 Receives National Award for Ongoing Safe Water Practices
  • 6/22/09 Zone 7 General Manager Declines Full Pay Increase
  • 5/21/09 Chris Moore Appointed to Fill Board Vacancy
  • 4/21/09 Free Water-Wise Gardening Workshop
  • 4/10/09 Zone 7 Board Member Announces Resignation
  • 3/20/09 Board Adopts New Storm Drainage Ordinance that Increases Fees on Development
  • 2/6/09 Development Fee Increase Proposed for Flood Protection, Storm Water Drainage Improvement


  • 12/18/08 Zone 7 Contributes to Environmental Study of Delta Solutions
  • 11/20/08 Zone 7 to Increase Wholesale Water Rates
  • 10/16/08 Board Postpones Action on Rates
  • 10/2/08 Approval of Water Legislation an Important First Step
  • 9/16/08 Zone 7 Board to Consider 16% Wholesale Water Rate Increase
  • 7/2/08 Zone 7 Joins Bay Area Regional Water Saving Hero Campaign
  • 6/25/08 New Toilet Rebates Help Residents Save More Water, More Money
  • 6/4/08 Drought Declaration Underscores Need to Conserve
  • 5/13/08 Zone 7 Reiterates Call for Water Conservation
  • 4/30/08 Zone 7 Goes Solar in Water Treatment
  • 4/29/08 Environmental Review Launched for Delta Conservation Plan
  • 4/18/08 Altamont Project Gets Underway
  • 2/29/08 Zone 7 Applauds Governor's Efforts on Delta
  • 2/21/08 Board Endorses Bay-Friendly Gardening Practices
  • 1/11/08 Public to Participate in Habitat Conservation Strategy


  • 12/18/07 Delta "Vision" for Water Conveyance Protects Valley Supplies
  • 12/7/07 Judgment Protects Drinking Water Quality for 25 Million Californians
  • 12/6/07 Zone 7 Recognized as Climate Action Leader
  • 10/18/07 Delta Issues, Conservation Help Drive Up Water Rates
  • 9/27/07 Delta Ruling Puts Pressure on Water Rates
  • 9/3/07 Court Ruling Taps Zone 7's Drought Supplies
  • 8/20/07 Arroyo Mocho Crossing Removed
  • 7/20/07 Water Saving Heroes
  • 6/26/07 Arroyo Mocho Crossing Removal Exemplifies StreamWISE Vision
  • 6/14/07 20% Voluntary Reduction in Water Use Sought
  • 6/8/07 Resumed Delta Pumping Helps Zone 7 Meet Critical Demands
  • 6/1/07 Zone 7 Responds to Delta Pump Shutdown
  • 5/17/07 New Facility Will Reduce Groundwater Hardness
  • 5/17/07 Six High School Students Win Contest
  • 5/3/07 Zone 7 Has New Logo!
  • 2/2/07 Lack of Rainfall Curbs Releases on Arroyo Mocho
  • 1/18/07 Zone 7 Launches Stream Management Implementation Plan
  • 1/2/07 Zone 7 Recognized for National Award


  • 12/21/06 New General Manager Selected for Zone 7
  • 11/16/06 Zone 7 General Manager to Retire
  • 11/16/06 Zone 7 Collaborates in Regional Water Management Plan
  • 10/19/06 Zone 7 Increases Wholesale Water Rates
  • 10/16/06 Steelhead Restoration Study Kicks Off
  • 10/13/06 Zone 7 Teams With Local Schools for World Monitoring Day
  • 9/21/06 Zone 7 to Consider Water Rate Increase
  • 9/7/06 Streambank Restoration Gets Under Way
  • 8/21/06 Zone 7 Board Approves Stream Management Master Plan
  • 8/17/06 Zone 7 Will Reduce Groundwater "Hardness"
  • 8/17/06 Zone 7 Board Supports Two Statewide Ballot Measures
  • 7/28/06 Drinking Water Safe, Despite Taste and Odor
  • 7/20/06 Zone 7 Swears in Board Members
  • 7/20/06 Zone 7 Joins in Bay-Delta Conservation Plan
  • 6/22/06 Zone 7 Reaches Agreement on Water Storage Project
  • 6/21/06 Lab Study Pinpoints Nitrate Sources in Valley Groundwater
  • 5/24/06 Zone 7 Hires Bonita Brewer as Communications Specialist
  • 5/18/06 Zone 7 Pitches in to Restore Steelhead in Alameda Creek
  • 5/2/06 SMMP Public Comment Period Extended
  • 3/16/06 Zone 7 to Implement Broad Approach to Local Stream Management
  • 1/19/06 Zone 7 Board Supports New Approach to Delta Management
  • 1/11/06 Zone 7 Directors to Consider Appointment of Christopher Moore to Board


  • 10/20/05 Zone 7 Approves Five Percent Rate Increase
  • 9/9/05 Zone 7 Contributes to Hurricane Katrina Recovery
  • 8/18/05 Zone 7 Approves Well Master Plan
  • 7/21/05 Zone 7 Receives National Recognition for Safe Water Partnership
  • 6/17/05 Zone 7 and DSRSD Plan for New Groundwater Demineralization Facility
  • 3/31/05 FY 2005/2006 Budget
  • 2/17/05 New Water Treatment Plant & Pipeline
  • 1/20/05 Recent Winter Storms Enhance Valley Water Supply