AO issued on 5/17/06. SYSTEM HAS TO COMPLY WITH THE RAD MCL AND PROVIDE PUBLIC NOTICE FOR PAST VIOLATIONS. System complied with the AO by promptly notifying U.S. EPA of the steps you had already taken to comply with the combined radium maximum contaminant level (MCL), and the steps you intended to take to achieve compliance with the AO. System also eventually provided detailed plans for coming into compliance with the combined radium MCL by December 31, 2006. By letter of December 20, 2006, system requested an extension of time until July 30, 2007 and provided justification, and also notified U.S. EPA about further delays and explained reasons. Treatment installation was completed in November 2007, and system monitored quarterly for combined radium until results from four consecutive quarters were at or below the MCL. System also provided public notice for quarterly combined radium MCL violations, as required by the AO. Letter teminating the AO was issued on 8/31/2009.