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City of Pleasanton Water Quality Division's Report on Water Quality Relative to Public Health Goals 2022 June 2022 -Page 7 of 8 BAT and Treatment Costs: Our water system is in full compliance with the Federal and State Lead and Copper Rule. Based on our extensive sampling, it was determined according to state regulatory requirements that we are below the Action Levels for both Lead and Copper. The SWRCB reviewed past residential tap results and determined that the City meets "optimized corrosion control" requirements for both constituents. In general, optimizing corrosion control is considered to be the best available technology to deal with corrosion issues and with copper findings. We continue to monitor our water quality parameters that relate to corrosivity twice a year. The constituents include pH, hardness, alkalinity and total dissolved solids. The City in cooperation with Zone 7 will take action if necessary to maintain its system in an "optimized corrosion control" condition. Since the City, in cooperation with Zone 7, is meeting the "optimized corrosion control" requirements, it is not prudent to initiate additional corrosion control treatment at this time to lower the copper level, as it involves the addition of other chemicals, which could raise additional water quality issues. Therefore, no estimate of cost has been included. Uranium The PHG for uranium is 0.43 picoCuries per liter(pCi/l)and the MCL is 20 pCi/l. Uranium is a naturally occurring metallic element which is weakly radioactive and is ubiquitous in the earth's crust. Uranium is found in ground and surface waters due to its natural occurrence in geological formations. One city well exceeded the PHG once during this period, at a result of 1.9 pCi/L. Zone 7 also sampled their sources for uranium and the range of results was ND(non-detect)up to 3 pCi/L. All sources were well below the MCL for uranium at all times during the period covered in this report. Health Risk Category: The category for health risk associated with uranium is that people who drink water containing uranium above the MCL for many years could experience an increased cancer risk. OEHHA has determined that the numerical cancer risk for uranium above the PHG level is 1x10-6, or one additional theoretical cancer cases in one million people drinking two liters of water a day for 70 years. BAT and Treatment Costs: There are several BATs designated to lower uranium to below the MCL including reverse osmosis (RO). Of the designated BATs for uranium, the most effective and economical approach would be to use RO treatment. 7