The Safe Drinking Water Act requires EPA to revise the existing 50 parts per billion (ppb) standard for arsenic in drinking water. On January 22, 2001 EPA adopted a new standard (read online) ~ (PDF file), and public water systems must comply with the 10 ppb standard beginning January 23, 2006. The Final August 2002 “Implementation Guidance for the Arsenic Rule and Clarifications to Compliance and New Source Contaminants Monitoring” and training information may be viewed at http://www.epa.gov/safewater/ars/implement.html.
Information about EPA’s arsenic small system treatment research program, including the application for EPA’s 2003 treatment demonstration studies, is available at http://www.epa.gov/ORD/NRMRL/arsenic.