The Safe Drinking Water Act (SDWA) requires EPA to publish a list of substances that could potentially be of concern and warrant further study, known as the Contaminant Candidate List (CCL), and anatoxin-a is on the list. In 2015, EPA submitted a report to Congress committing to collecting additional information on anatoxin-a.
Under the SDWA, EPA is also required once every five years to issue a new list of up to 30 unregulated contaminants to be monitored by public water systems. This is known as the Unregulated Contaminant Monitoring Rule. Anatoxin-a is included in the fourth round of UCMR (UCMR4). Testing for UCMR4 starts in January 2018 and will continue through December 2020. The data from this nationwide monitoring will inform and support EPA’s decisions on regulatory actions to protect public health.