The purpose of this notice is to provide water quality details for the source water blend change starting as early as January 13, 2020. With commencement of the startup testing of the Regional Groundwater Storage and Recovery (GSR) Project, groundwater will be blended with surface water in the Regional Water System (RWS) over the next several months during the testing phase.
The GSR Project consists of eight newly constructed groundwater wells connected to the SFPUC RWS transmission lines. Startup testing will begin at the F Street Well and Treatment Station. Testing will begin with one well at a time, then continue with various combinations. The groundwater will have chlorine, pH and fluoride levels consistent with levels in the RWS. Customers that are expected to receive a blend of groundwater from the Regional GSR Project include Brisbane, Cal Water Bayshore District (South San Francisco and Colma), Daly City, Millbrae, San Bruno, San Francisco Airport, Westborough Water District, and San Francisco.
The following table shows calculated water quality values for the blended water in comparison with water from the Harry Tracy Water Treatment Plant (HTWTP) and Irvington Portal. During this testing phase, groundwater will be introduced to San Andreas Pipeline No. 2, San Andreas Pipeline No. 3, Sunset Supply Pipeline, and/or Crystal Springs Pipeline No. 2. The water quality parameters below represent an estimate of how the blend parameters will change with the addition of groundwater which will vary as the operation of the groundwater wells will be intermittent during the testing phase.
Please call the SFPUC Water Quality Division at 650-652-3100 if you have any questions.