California started to regulate perchlorate in drinking water in Oct. 2007, setting the Maximum Contaminant Level (MCL) at 6µg/L. In 2015, the state also established the Public Health Goal (PHG) for perchlorate at 1 µg/L, superseding the PHG of 6µg/L established in 2004. Massachusetts has even lower level at 2µg/L. More than 10 other states have similar health-based goals or advisory levels for perchlorate in drinking water.
The US EPA placed perchlorate in the first Contaminant Candidate List (CCL1) in 1998 and determined that perchlorate meets the Safe Drinking Water Act’s criteria for regulation as a contaminant in Feb. 2011. However, the regulatory standards for perchlorate have not yet been determined.