The previous drinking water standard for arsenic, 50 ppb, was set by the U.S. Public Health Service in 1942. EPA adopted that level and issued an interim drinking water regulation for arsenic in 1975. In 1986, Congress amended the Safe Drinking Water Act (SDWA), converted all interim standards to National Primary Drinking Water Regulations, and included arsenic on a list of 83 contaminants for which EPA was required to issue new standards by 1989. In the final rule, published on January 22, 2001 (66 FR 6976), EPA set the standard at 10 ppb and applied it to non-transient, non-community water systems, as well as community water systems. Congress took issue with EPA's assessment that small system variance technologies were not merited for the arsenic standard, and in 2002, directed EPA to review the criteria it uses to determine whether a compliance treatment technology is affordable for small systems. Arsenic Rule Review

EPA issued the final rule on January 22, 2001. In March 2001, the Administrator delayed the rule for 60 days, citing concerns about the science supporting the rule and its estimated cost to communities. On May 22, 2001, EPA delayed the rule's effective date until February 22, 2002, but did not change the 2006 compliance date for water systems (66 FR 28342). In October 2001, EPA affirmed that 10 ppb was the appropriate standard and announced plans to provide $20 million for research on affordable treatment technologies to help small systems comply. The conferees expressed concern that the new requirements could pose a "huge financial hardship" for many rural communities. Various bills were offered to promote small system compliance by providing technical assistance, financial assistance, and/or compliance flexibility. None of these bills was enacted. Arsenic-specific legislation has again been offered in the 111 th Congress, although broader infrastructure bills have received wider attention.
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. Similar legislation again has been offered in the 111th Congress, while broader infrastructure financing bills have received greater congressional attention.