Arsenic Rule Implementation

On January 22, 2001 EPA adopted a new standard for arsenic in drinking water at 10 ppb, replacing the old standard of 50 ppb.  The rule became effective on February 22, 2002.  The date by which systems must comply with the new 10 ppb standard is January 23, 2006. 

Final Implementation Guidance for the Arsenic Rule

The final Implementation Guidance for the Arsenic Rule is based on the final rule published in the Federal Register on January 22, 2001. It incorporates comments received on the previous draft implementation guidance's, and from the training sessions on the arsenic rule held throughout the country. The guidance summarizes key sections of the Proposed Rule and provides a "how to approach" for EPA Regions and States to implement the regulation. It contains an explanation of the rule's requirements and guidance for preparing State primacy revision applications. The document incorporates comments received from Regions, States, technical assistance providers, water systems, and others.

Minor Clarification of National Primary Drinking Water Regulation for Arsenic - Final Rule

EPA is affirming that the public health standard for arsenic in drinking water established in January 2001 is 10 parts per billion (ppb). In today’s action, EPA is making clear that when a monitoring result is expressed in milligrams per liter (mg/L) rather than ppb, that any monitoring result greater than 0.010 mg/l is a violation of the January 2001 arsenic standard. To assure that this clarification extends to the regulatory text for arsenic and to remove any implementation uncertainty relating to this issue, EPA has amended the arsenic Maximum Contaminant Level (MCL) to express it as 0.010 mg/l.