A recent New York Times article has started some conversation about arsenic in water. The article focuses on a mobile home park in California where approximately 1,000 people live in 230 units. Some of the residents have reported symptoms ranging from “persistent rashes and hair loss to kidney disease… and even cancer.”

Whatever the cause of the residents’ symptoms, it’s worth taking a moment to consider why water utilities monitor for arsenic in drinking water. Arsenic is tasteless and odorless, and occurs naturally in the Earth’s soils, rocks and minerals. It’s also used in industry as a wood preservative, in paints, metals, drugs and for a variety of other purposes. It is lethal in very high doses. You can learn more in the AWWA book Plain Talk about Drinking Water.

Arsenic can also enter drinking water supplies from agricultural and industrial activities, or through groundwater that flows through natural arsenic deposits. It is regulated by the U.S. Environmental Protection Agency (EPA) through the Arsenic Rule, which has been in place since 2001. The rule, which is applicable to all community water systems, sets a standard for arsenic in drinking water of 10 parts per billion.

If you receive your water from a drinking water utility, you can have confidence that it is monitoring and treating for arsenic. Your consumer confidence report – available from your utility upon request and distributed at least once per year – carries results of the testing.

If you get your water from a private well, you should be testing for arsenic and other potential contaminants. EPA provides some helpful guidance. The National Ground Water Association also has tips for dealing with arsenic in drinking water.