Public water systems in Arizona were required to comply with the revised arsenic MCL of 10 ug/L by January 23, 2006. On August 6, 2007, the City requested that EPA exempt the City from the January 23, 2006 arsenic MCL compliance deadline. EPA approved the exemption and the City was granted a new arsenic compliance deadline until January 23, 2009. The City failed to comply with the revised MCL for arsenic by January 23, 2009. The EPA Order requires the City to submit a compliance plan and schedule intended to bring the City into compliance with arsenic MCL by June 30, 2011.