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in local groundwater and in MWDSC surface water below the PHG) was calculated. Because the DLR for gross alpha is 3 pCi/I, treating gross alpha to 0 pCi/I means treating it to below the DLR of 3 pCi/I. Achieving the water quality goal for gross alpha could range from $9,180,000 to $78,500,000 per year, or between $203 and $1,735 per household per year. Perchlorate — The BATs for removal of perchlorate in water are: ion exchange and biological fluidized bed reactor. Perchlorate was detected above the PHG in the local groundwater (Wells 18, 21, 24, and 36). The City is in compliance with the MCL for perchlorate. The estimated cost to reduce perchlorate levels in local groundwater to below the PHG of 1 pg/I using ion exchange was calculated. Because the DLR for perchlorate is 2 pg/I, treating perchlorate to below the PHG level means treating perchlorate to below the DLR of 2 pg/I. There are numerous factors that may influence the actual cost of reducing perchlorate levels to the PHG. Achieving the water quality goal for perchlorate could range from $1,040,000 to $2,270,000 per year, or between $23 and $50 per household per year. All Contaminants — In addition, a cost estimate to treat all water produced or purchased by the City using ion exchange and reverse osmosis to remove all the contaminants detected above the PHGs or MCLGs was calculated. All the contaminants listed in the accompanying chart may be removed to non -detectable levels by ion exchange and reverse osmosis. As shown on the accompanying chart, achieving the water quality goals for all contaminants using ion exchange and reverse osmosis could range from $10,200,000 to $80,800,000 per year, or between $226 and $1,785 per household per year. For additional information, please contact Mr. Robert Hernandez, Water Services Quality Supervisor, at (714) 647-3341, or write to the City of Santa Ana, 220 South Daisy Avenue, Santa Ana, California 92703. J:\2605\2605-003 - Santa Ana 2022 PHG\Santa Ana 2022 PHG text Final.docx City fity ouncil 23 — 10 port