Perchlorate can interfere with iodide uptake into the thyroid gland. The thyroid is a central control point for a variety of hormonal responses including iodine levels. In adults, the thyroid helps to regulate metabolism. In pregnant women, severe iodide deficiency can result in major neurodevelopmental deficits and goiter in their offspring. Lesser degrees of iodide deficiency may also cause important neurodevelopmental deficits in infants and children.

Perchlorate is highly soluble in water and has been detected in ground and surface water in 26 states and one territory. While it has often been detected in water supplies in close proximity to sites where solid rocket fuel is manufactured or used, there are also many locations in the United States lacking a clearly defined source.

Perchlorate is not currently regulated by the U.S. Environmental Protection Agency. In 2005, EPA announced it had set a reference dose of 0.0007 mg/kg for perchlorate, following a recommendation from the National Academies of Science. This translates to a Drinking Water Equivalent Level of 24.5 ppb.

In 2011 the EPA made a final regulatory determination that perchlorate meets the Safe Drinking Water Act's criteria for regulating a contaminant and it intends to initiate a rulemaking process to develop a national primary drinking water regulation for perchlorate.

Several states have initiated regulatory reviews to prepare a drinking water standard for perchlorate. California and Massachusetts have set "public health goals" for the contaminant levels of 6ppb and 1ppb respectively.

If you are concerned about perchlorate in your drinking water, you may consider purchasing a home treatment device. However, in order to make a well-informed and cost-effective decision, consider:

• Checking with your water system or consumer confidence report to learn about the amount of total perchlorate in your water.
• Identifying a device that has been independently certified to remove perchlorate.

NSF International, the Water Quality Association, Underwriters Laboratories and CSA International all certify home treatment products for removal of contaminants. The relevant perchlorate removal standard is NSF/ANSI Standard 58. If you choose to use a home treatment device, it is very important to follow the manufacturer's operation and maintenance instructions carefully in order to make sure the device works properly.