US Court of Appeals Decision Mandates SDWA Regulation for Perchlorate

On May 9, the U.S. Court of Appeals for the District of Columbia reinstated EPA’s 2011 determination to regulate perchlorate under the Safe Drinking Water Act (SDWA). The court ruled that the Agency’s reasoning was not adequate to uphold its decision and authority to withdraw the determination in 2020, based on the prevalence of perchlorate in drinking water and new information about associated health impacts. The court action stemmed from a Natural Resources Defense Council (NRDC) lawsuit and challenge against the Agency’s decisions. The Trump administration’s decision to withdraw the regulatory determination for perchlorate in 2020 was also upheld by the Biden administration. However, EPA will now have to move forward with the SDWA regulatory development process. For more information about EPA perchlorate actions, visit the EPA website at