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BACKGROUND Perfluorohexanesulfonic acid (PFHxS) is a member of a large class of chemicals known as per- and polyfluoroalkyl substances (PFAS). New health-based notification and response levels have been established for PFHxS. The City's Well 8 was taken offline when it exceeded these notification and response levels in 2019. PFHxS concentration in City's remaining two water supply Wells 5 and 6 exceeded the new notification and response levels such that in November 2022 Wells 5 and 6 were taken out of operation. Consequently, the City no longer has access to its annual 3,500 Acre-Feet (AF) groundwater supply. DISCUSSION Current Condition Without access to its groundwater supply, the City must get replacement water from Zone 7 through seven connections to Zone 7's regional distribution system. Zone 7 confirmed that it can deliver the 3,500 AF of replacement water; however, there was some uncertainty around the summer peak demand, so testing was needed. The connections are known as turnouts and are numbered one through seven. As shown in Figure 1, replacement water will come from Turnouts (TO 1-5) - noted by the red circles — and enters the City's lower pressure zone shown as the blue area. Figure 1. Turnout Location Map o / `10 16 36 - ^ Js JBLIN CANYON TANK S �o o ,6 URNOUT'43 TURNOUT Adi 1 16 s FOOTHILL TANK r TURNOUT01 EL CREEK TANK err 9 `�SQox ? K. R,�1 'Z 9 HOLLER 7.70 TANK ^ �' 0 TURNOUTia2 a O*iJno��OtS1D'1�. x�' 'sl � LYEL•L 7 WELL 8 1 VALLEY AV v 20 i�:; Fes......-. a WELL 6 16 WELL 5 e y� TANK-900 � •".f o 16 `��i � URNOUT tt5 TANK 510 36 TANK 1300 — BERNAL AV' !S ^(p A BONDS-1 16 16 i AA iTANKs770.1 /SYCAMORE TANK KOTTINGER Page 2 of 5