Perchlorate & Water

Perchlorate and Water

Until the late 1990's, perchlorate was detected only in a few places where it was either manufactured or used in large quantities. In 1997, new techniques were developed that made it possible to detect perchlorate in water at very low levels, at about 4 parts per billion (ppb). Because of these advancements, low levels of perchlorate have been detected in water supply systems in California, Nevada, Arizona and elsewhere.

In 2006, U.S. EPA conducted a study to help determine the occurrence of perchlorate in water across the country. EPA tested 34,193 samples from US public water systems. Of those, only 637 samples (1.86 percent) had perchlorate levels above 4 ppb. Half of those 637 samples (i.e., 319) were in the range of 4 ppb to 6.4 ppb. Thus, perchlorate levels were less than 6.4 ppb in more than 99 percent of water samples tested.
Read the EPA study »

The scientific database on perchlorate and human health is very robust and as a result, much is known about how perchlorate works in the body. Peer-reviewed scientific and medical studies conducted over a broad range of exposure levels in humans show that perchlorate in drinking water below 245 ppb has no measurable effect on human health.

Even so industry, working with state and federal regulators has been implementing treatment technologies in several parts of the country, to remediate affected water supplies.
Learn more about perchlorate removal technologies »

Citizens interested in learning about the perchlorate levels found in their water supply should call their local water company. Or, if their water service is provided by a municipal utility, citizens can contact the customer service center (usually listed on their utility bill) and get information on how to contact their water purveyor. Citizens can also visit the water supplier's website to look for either the water quality report or the Consumer Confidence Report.