EPA’s 24.5 ppb reference dose (the maximum dose without any risk, abbreviated RfD) may be used by officials across the U.S. to make site-specific cleanup or interim drinking water standard decisions involving perchlorate. States and private parties also may look to EPA’s RfD and Drinking Water Equivalent Level (DWEL) to make similar decisions.

In February 2011, despite evidence in the scientific record that perchlorate does not meet the requirements for regulation under the federal Safe Drinking Water Act, U.S. EPA decided to move forward in setting a drinking water standard for perchlorate. The EPA’s determination began a multi-year process involving several opportunities for public comment. Barring any decision to pause or stop the process, the EPA’s next step is to issue a draft standard for public comment.