EPA Publishes Final Fifth Contaminant Candidate List for Potential Drinking Water Regulations

EPA has published the Final Fifth Drinking Water Contaminant Candidate List (CCL 5). EPA will use the CCL 5 to consider whether to develop regulations over the next five-year cycle under the Safe Drinking Water Act. The Final CCL 5 includes 66 individually listed chemicals, a grouping of PFAS compounds, groups of cyanotoxins and disinfection byproducts (DBPs), and 12 microbes. Exhibit 1b on page 18 of the Prepublication Version of the Federal Register (FR) Notice includes the full list of unregulated DBPs. The group of cyanotoxins includes, but is not limited to anatoxin-a, cylindrospermopsin, microcystins, and saxitoxin. Within the final CCL 5, the Agency outlines what is included under a broad definition for PFAS. It is important to note that this definition is only applicable to CCL 5, and EPA does not plan to use this definition beyond CCL 5 at this time. Additionally, PFOA and PFOS are not included within this grouping as these two chemicals are already in the process of being regulated.

EPA considered recommendations and comments from the public as part of the process for developing the final list of contaminants, as well as comments on previous CCLs. These included prioritizing data most relevant to drinking water exposure, improving considerations of sensitive populations including children, and considering the recommendations from the Science Advisory Board Review of the EPA’s Draft CCL 5. These improvements resulted in a Final CCL 5 that can better inform prioritization of contaminants for potential regulatory actions and/or research efforts. For more information and to read the fact sheet and frequent questions, visit the EPA CCL 5 website.