Arsenic in Drinking Water: Regulatory Developments and Issues

Mary Tiemann
Specialist in Environmental Policy

The Safe Drinking Water Act Amendments of 1996 (P.L. 104-182) directed the Environmental Protection Agency (EPA) to update the standard for arsenic in drinking water. In 2001, EPA issued a new arsenic rule that set the legal limit for arsenic in tap water at 10 parts per billion (ppb), replacing a 50 ppb standard set in 1975, before arsenic was classified as a carcinogen. The arsenic rule was to enter into effect on March 23, 2001, and water systems were given until January 2006 to comply. EPA concluded that the rule would provide health benefits, but projected that compliance would be costly for some small systems. Many water utilities and communities expressed concern that EPA had underestimated the rule's costs significantly. Consequently, EPA postponed the rule's effective date to February 22, 2002, to review the science and cost and benefit analyses supporting the rule. After completing the review in October 2001, EPA affirmed the 10 ppb standard. The new standard became enforceable for water systems in January 2006. 

Since the rule was completed, Congress and EPA have focused on how to help communities comply with the new standard. In the past several Congresses, numerous bills have been offered to provide more financial and technical assistance and/or compliance flexibility to small systems; however, none of the bills has been enacted. Although arsenic-specific legislation has not been offered in the 111th Congress, broader infrastructure financing bills have received attention.


Date of Report: January 29, 2010
Number of Pages: 9
Order Number: RS20672
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