Question:
The EPA's provisional drinking water equivalent level (DWEL) for perchlorate is 4 - 18 parts per billion (ppb). Is this the allowable level of perchlorate in bottled water?

Answer: EPA's provisional DWEL of 4 - 18 ppb for perchlorate is based on its provisional RfD range of 0.1 - 0.5 micrograms per kilogram per day (7 - 35 µg/day for a 70 kg adult). EPA has not yet set an allowable level, or maximum contaminant level (MCL), for perchlorate in drinking water.

EPA is developing information on the health effects, the occurrence in public water systems, analytical methods, and treatment techniques with respect to perchlorate that will be used to decide if a drinking water standard is warranted.

If EPA establishes a standard, e.g., an MCL, for perchlorate in public drinking water, FDA will establish an allowable level for perchlorate under the quality standard regulations for bottled water.