The Lessalt Water Treatment Plant, located at the corner of Sunnyslope Rd. and Fairview Rd. treats raw surface water to potable drinking water standards. This raw surface water is delivered to Lessalt from San Luis Reservior via the Pacheco Tunnel and the Hollister Conduit as part of the Central Valley Project (CVP) by the Bureau of Reclaimation and San Benito County Water District. Treated water from Lessalt is regularly tested to ensure it meets all State and Federal health requirements and guidelines. The water then enters the Sunnyslope water distribution system and is delivered directly to customers.

The treated surface water from Lessalt has significantly less hardness and minerals than the local groundwater. For this reason, Sunnyslope and Hollister strive to maximize the use of this water to provide higher quality water to our customers. 

Lessalt was origianlly constructed through a joint partnership between the City of Hollister and Sunnyslope County Water District in 2002. It received a major upgrade in 2014 as part of the Hollister Urban Area Water & Wastewater Master Plan (HUAMP) during which ownership of the plant was transferred to San Benito County Water District. However, Sunnyslope staff continue to conduct the daily operations and maintenance of the plant.