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Water: Contaminant Candidate List

CCL and Regulatory Determinations Home

EPA has national primary drinking water regulations for more than 90 contaminants. The Safe Drinking Water Act (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 periodically publish this list of 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.


  • Basic Information - This page answers questions about how the CCL is developed, how it fits into the regulatory development process and links to data and information on CCL contaminants.
  • CCL 3 List - This page describes the CCL 3 process and offers an opportunity to comment on the process and contaminants included on the draft CCL 3.
  • CCL 2 List and Regulatory Determinations - These pages provide the contaminants listed on the second CCL and the CCL 2 Regulatory Determinations.
  • CCL 1 List and Regulatory Determinations -These pages provide the contaminants listed on the first CCL and the CCL 1 Regulatory Determinations.

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