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Six-Year Review of Drinking Water Standards

Six-Year Review & Other Related Links

The Safe Drinking Water Act (SDWA) requires EPA to review each National Primary Drinking Water Regulation (NPDWR) at least once every six years and revise them, if appropriate. The purpose of the review, called the Six-Year Review, is to identify those NPDWRs for which current health effects assessments, changes in technology, and/or other factors provide a health or technical basis to support a regulatory revision that will maintain or strengthen public health protection. 

Statutory Requirements for the Six-Year Review

Section 1412(b)(9) of the Safe Drinking Water Act states,

"The Administrator shall, not less often than every 6 years, review and revise, as appropriate, each national primary drinking water regulation promulgated under this title. Any revision of a national primary drinking water regulation shall be promulgated in accordance with this section, except that each revision shall maintain, or provide for greater, protection of the health of persons."

Overview of the Six-Year Review Efforts

Since the 1996 SDWA Amendments were enacted, the Agency has completed two comprehensive reviews of existing National Primary Drinking Water Regulations.  The links below provide more information about the first and second Six-Year Reviews.

Other Related Efforts

In a related effort, SDWA includes a process that we must follow to identify and list unregulated contaminants which may require a national drinking water regulation in the future. EPA must publish this list of unregulated contaminants (called the Contaminant Candidate List or CCL) and decide whether to regulate at least five or more contaminants on the list (called Regulatory Determinations). EPA uses this list of unregulated contaminants to prioritize research and data collection efforts to help us determine whether we should regulate a specific contaminant.

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