Key drinking water issues include problems caused by specific contaminants, such as the gasoline additive methyl tertiary butyl ether (MTBE), perchlorate, and lead, as well as the related issue of the appropriate federal role in providing financial assistance for water infrastructure projects. Congress last reauthorised the Safe Drinking Water Act (SDWA) in 1996, and although funding authority for most SDWA programs expired in FY2003, broad reauthorization efforts are not expected as EPA, states, and water utilities remain busy implementing the requirements of the 1996 amendments. Concerns about perchlorate in drinking water also have returned to the congressional agenda, after the past Congress enacted several provisions on this issue. H.R. 213 has been introduced to require EPA to set a drinking water standard for perchlorate in 2007, and a January 2005 National Academy of Sciences report on the health effects of perchlorate has increased oversight interest in perchlorate regulatory activities at EPA. Concerns over the security of the nation's drinking water supplies were addressed by the 107th Congress through the Bioterrorism Preparedness Act (P.L. 107-188), which amended SDWA to require community water systems to conduct vulnerability assessments and prepare emergency response plans. Subsequent congressional action has involved oversight and funding of water security assessment and planning efforts and research. An ongoing SDWA issue involves the growing cost and complexity of drinking water standards and the ability of water systems, especially small, rural systems, to comply with standards. The issue of the cost of drinking water standards, particularly the new arsenic standard, has merged with the larger debate over the federal role in assisting communities with financing drinking water infrastructure - an issue that has become more challenging in a time of tightened budgets. Congress authorized a drinking water state revolving fund (DWSRF) program in 1996 to help communities finance projects needed to meet standards. For FY2005, Congress provided $843 million for the DWSRF program, and the President has requested $850 million for FY2006. Notwithstanding this program, studies show that a large funding gap exists and will grow as SDWA requirements increase and infrastructure ages.