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groundwater sources in the Pleasanton area include: 1) Chain of Lakes Wellfield, 2) Stoneridge Well, 3) Mocho Wellfield, and 4) Hopyard Wellfield. At these locations, all groundwater is chloraminated for disinfection residual and then pumped into the same transmission lines as the surface water. At the location of the Mocho Wellfield, Zone 7 operates the Mocho Groundwater Demineralization Plant where some groundwater can be sent through reverse osmosis membranes to reduce the concentration of minerals in the groundwater. Once in the transmission lines, treated water is delivered to the Tri- Valley Water Retailers via turnouts. Turnouts are facilities that physically connect Zone 7's transmission lines to each Tri-Valley Water Retailer's distribution systems. At these turnouts, flow is controlled and metered for administration and operational purposes. Water is not treated at the turnouts as it has already been treated for drinking purposes by Zone 7 at their treatment plants and groundwater well facilities. The exception is that the City does add fluoride at the turnouts due to requirements specific to the City that are not applicable to some of the other Tri-Valley Water Retailers. Zone 7 has seven City turnouts of which Turnouts 1 and 2 are currently inactive. Refer to Attachment 1 - Figure 1 for an illustration of Zone 7's existing system including treatment plants, groundwater wells, transmission piping, and turnout facilities. The City's water source is groundwater. The City has three groundwater wells that together are allowed an annual pumping quota of 1,140 million gallons. Refer to Attachment 1 - Figure 2 for the location of the City's groundwater wells in relation to the Zone 7 turnouts into the distribution system. All groundwater is chloraminated for disinfection residual, treated with fluoride, then pumped directly into the City's distribution system. Table 1 below provides a breakdown of the water supply utilized for the City in 2018. Table 1 — City Water Supply 2018 Zone 7 Turnouts Million Gallons Percent of Total Turnout 1 0 0% Turnout 2 0 0% Turnout 3 992 22% Turnout 4 914 20% Turnout 5 867 19% Turnout 6 440 10% Turnout 7 179 4% Subtotal 3,392 75% City Groundwater Wells Well 5 288 6% Well 6 402 9% Well 8 449 10% Subtotal 1,139 25% Total 4531 100% Page 3 of 13