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• Identify each contaminant that exceeds the applicable State PHG; • Disclose the associated public health risks at both the current enforceable drinking water standard (MCL), and the PHG; • Identify the best available technology for treatment; and • Estimate the aggregate cost associated with reducing the contaminant to below the PHG. PHGs were exceeded for copper and uranium. The 2019 copper samples showed a value for copper of 0.65 mg/L, which is over the PHG of 0.3 mg/L, but below the action level of 1.3 mg/L. The PHG for uranium is 0.43 pico Curies per liter (pCi/I) and the MCL is 20 pCi/I. One city well exceeded the PHG once during the three-year period, with a result of 1.9 pCi/L. The health risks associated with copper and uranium are summarized: Copper is an essential nutrient, but at high doses it has been shown to cause stomach and intestinal distress, liver and kidney damage, and anemia; OEHHA has identified uranium as a carcinogen. The best available treatment technology to address both copper and uranium is to install and operate a reverse osmosis system. According to the Association of California Water Agencies (ACWA) Cost Estimates for Treatment Technology, reverse osmosis systems cost between $2.04- $8.04 per 1,000 gallons of water treated. Over the last three years, the City averaged 2.9 million gallons of water per day from its wells; to install and operate a reverse osmosis system, the cost could be as much as $10.7 million/year for the life of the system. The cost per customer service connection could be as high as $486 per year. There would also be additional costs for water conditioning to ensure water treated by reverse osmosis is optimized for distribution system corrosion control. The drinking water quality in the City of Pleasanton meets all State of California drinking water standards set to protect public health. The effectiveness of the reverse osmosis treatment processes to provide any significant reductions in constituent levels at these already low values is uncertain, and the health protection benefits of these potential reductions are not clear and may not be quantifiable. Therefore, given the high costs and uncertain benefits, staff does not recommend the City consider reverse osmosis treatment at this time. Submitted by: Fiscal Review: Approved by: /ra4'Pti— /j(tyL_. Tamara Baptista Susan Hsieh Gerry Beaudin Interim Director of Operations Director of Finance City Manager and Water Utilities Attachments: 1. City of Pleasanton 2022 Public Health Goals Report Page 5 of 5