The U.S. Environmental Protection Agency (EPA) announced Draft Contaminant Candidate List 5 (CCL 5), which provides the latest list of drinking water contaminants that are known or anticipated to occur in public water systems and are not currently subject to EPA drinking water regulations. As directed by the Safe Drinking Water Act, EPA’s CCL 5 identifies priority contaminants to consider for potential regulation to ensure that public health is protected.
“This important step will help ensure that communities across the nation have safe water by improving EPA’s understanding of contaminants in drinking water,” said EPA Assistant Administrator for Water Radhika Fox. “On PFAS, the agency is working with the scientific community to prioritize the assessment and regulatory evaluation of all chemicals as contaminants.”
The Draft CCL 5 includes 66 individual chemicals,12 microbes, and three chemical groups – per- and polyfluoroalkyl substances (PFAS), cyanotoxins, and disinfection byproducts (DBPs). These contaminants have been identified as agency priorities and contaminants of concern for drinking water. PFAS are proposed as a group, with the exception of PFOA and PFOS because the agency is moving forward with national primary drinking water standards for these two contaminants. This action is in keeping with the agency’s commitment to better understand and ultimately reduce the potential risks caused by PFAS.
CCL 5 was developed under an improved process that included new approaches to rapidly screen a significantly larger number of contaminants, prioritizing data most relevant to drinking water exposure and the potential for the greatest public health concern, and better consideration for sensitive populations and children. EPA continues to collect data and to encourage further research on the listed contaminants to better understand potential health effects from drinking water exposure before making any regulatory determinations.
EPA plans to consult with the Science Advisory Board (SAB) on the Draft CCL 5 in the fall of 2021. The agency will consider public comments and SAB feedback in developing the Final CCL 5, which is expected to be published in July 2022. After a final CCL is published, the agency will undertake a separate regulatory determination process to determine whether or not to regulate contaminants from the CCL.
Developing the CCL is the first step under the Safe Drinking Water Act (SDWA) in potentially regulating drinking water contaminants. SDWA requires EPA to publish a list of currently unregulated contaminants that are known or anticipated to occur in public water systems and that may require regulation. EPA must publish a CCL every five years. The CCL does not create or impose regulatory burden on public water systems or state, local, or Tribal governments. EPA has completed four rounds of CCLs since 1996. The last cycle of CCL, CCL 4, was published in November 2016. EPA began the development of the CCL 5 in 2018 by asking the public to nominate chemicals, microbes, or other materials for consideration for the CCL 5. The agency received 89 nominations and evaluated the nominated contaminants and other contaminant data and information in developing the Draft CCL 5.