Chemicals chlordane and dieldrin — termite pesticides deemed toxic to humans and banned in the U.S. over three decades ago — have become a concern in lower Fairfield county water wells and the New Canaan Health Department is recommending residents test their well water according to Center for Disease Control (CDC) guidelines.

"This has come up in Stamford and, if you look at the map, it's all over," said New Canaan Health Director Dr. David M. Reed, "It's all over the country, so there are probably houses in New Canaan with these chemicals. It's unknown, so all you can do is test. There's no magical line between Stamford and New Canaan."

Over 30 percent of private well water tested in Stamford and Wilton since 2009 tested positive for unsafe levels of the pesticides.

According to Reed, chlordane and dieldrin were injected straight into the soil around houses in order to control termites, making the chances of leaching into well water most probable.

The Connecticut Department of Public Health (DPH) recommends that private wells be tested annually for a full spectrum of contaminants, including, but not limited to: radon, arsenic, pesticides, chemicals, and sewer overflow.

The CDC reminds residents that the Environmental Protection Agency (EPA) is not responsible for testing and maintaining private wells.

The Conn. DPH provides a list of 31 in-state approved laboratories certified to test drinking water for a variety of toxins (follow the link to access the list). If contaminants are detected, a Granular Activated Carbon (GAC) filter, which requires the monitoring of replaceable carbon canisters to maintain optimum filtering, may be installed for a fee.

For more information, please find the useful contacts below:

New Canaan Health Department:
Briggs Geddis - (203) 594-3018

Connecticut DPH-Environmental Health:
Sheree Rusnak - (860) 509-7740

Connecticut DPH-Well Water:
Ray Jarema - (860) 509-7321

Connecticut Department of Environmental Protection:
Amanda Flad - (860) 424-3351