Thacher Tank

The newest addition to the SCMWC system is the 708,000-gallon Thacher Tank.  This tank, located high on The Thacher School campus, is SCMWC’s main storage tank.  Canyon water flows into this tank, and then into the SCMWC system.  The tank has a pressure-monitoring device that measures the volume in the tank and automatically activates the intertie with CMWD at the McAndrew Pump Station when the tank water level drops below a certain point. 

The new tank replaces a 60-year-old tank that had a capacity of only 125,000 gallons.  On a hot summer day, the old tank would empty and refill four to six times, and at night would fill after demand dropped, usually about 9 PM, and then overflow into surface drainages after filling.  Over the past 10 years, the tank developed serious and expensive leaks, and in 2016, the Board approved the construction of the new, larger tank. 

In August of 2020, the old tank was removed and the new one installed.  The new tank’s higher volume benefits the Company in multiple ways.  First, it greatly increases fire security with more than five times the volume of the old tank.  Second, when necessary, it enables the pumping of CMWD water at off-peak hours, thereby saving Edison power costs.  Finally, the larger capacity optimizes the use of the water the company produces, and further minimizes the need to purchase CMWD water.