Portland to request variance to water treatment requirement

by Melanie Davis
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Portland, OR — The Portland Water Bureau announced Jan. 3 its intent to develop a request for a variance to the treatment requirements of a federal water treatment rule after a year of tests came up negative for the parasite Cryptosporidium. The variance, if recommended by the federal EPA and granted by the Oregon Department of Human Services Drinking Water Program, would enable the city to avoid much of the $100 million in expenses required to design and build a water treatment facility at the city's Bull Run watershed to address Cryptosporidium. "Portland has been conducting extensive water quality sampling looking for Cryptosporidium within the Bull Run for the last year — 449 individual tests at the drinking water intake (totaling over 10,250 liters) and more than 300 at upstream locations," said Water Bureau Administrator David Shaff. "This sampling effort is probably the most intensive screening for Cryptosporidium in a protected watershed ever conducted within the United States. The results are now in and there were zero instances of Cryptosporidium. We therefore believe we have a very good case to make that the Water Bureau can continue its century long stewardship of the Bull Run in support of public health without constructing a treatment facility for Cryptosporidium." The treatment variance is a provision of the Safe Drinking Water Act (SDWA) that provides for an alternative form of compliance with federal drinking water rules if a public water system can demonstrate that a required treatment is not necessary to protect public health due to the nature of the system's raw water source. The State Drinking Water Program has legal primacy over the federal regulation, but has formally asked the EPA to retain its lead role in evaluating Portland's variance request. Therefore the city anticipates working closely with both the state and EPA during this process. Portland began intensive water quality monitoring in December 2009 to gather evidence relevant to the question of whether the Bull Run watershed was at risk of delivering the type and quantity of Cryptosporidium that can cause illness if consumed. Roughly 200 liters of water were tested each week through December 2010 at the intake where raw water from the Bull Run reservoirs first enters the drinking water system. The bureau augmented this testing with regular sampling at nine upstream locations in the watershed to determine if there were any so-called "hot spots" where Cryptosporidium might be entering the Bull Run River or the two drinking water reservoirs. No Cryptosporidium was found in any of the tests at any of the locations. The results of the intensive monitoring build on previous routine testing results which document that Cryptosporidium has not been detected in the watershed since September 2002.