Backflow Prevention

The Village of Clarendon Hills Cross Connection Control Program is designed to safeguard public health by protecting the municipal drinking water supply. Your cooperation is essential. In compliance with IEPA (Illinois Environmental Protection Agency), all Backflow Prevention Devices are required by State mandate to be tested annually by a Certified Plumber or Certified Irrigation Company. Test results can be submitted to the Village of Clarendon Hills via email to 

The Illinois Environmental Protection Agency (IEPA) also requires every water supply provider to develop and implement a backflow prevention control program. The program mandates surveying all residential water customers every two years to identify and eliminate connections that could allow contaminants to accidentally flow back into the drinking water from sources such as fire protection sprinkler systems, boilers, lawn sprinklers and swimming pools.


​What is a cross connection?

A cross connection is a connection between a potable water supply and a non-potable source, where a contaminant potentially could enter the drinking water supply. Cross connections should be protected by a valve called a backflow preventer.

What is a backflow preventer?

A backflow preventer is a device that allows the water to flow only in one direction and prevent a pipe or device connected to the water supply line to allow water to flow back into the municipal supply system.

​Who has the responsibility for installing and maintaining backflow preventers? 

Property owners are responsible for installing, testing and maintaining backflow preventers. Water customers must contract with a licensed professional to perform the required annual tests and make any necessary repairs. Most plumbing contractors can install and repair backflow preventers and are certified to test them


​Where should a backflow preventer be installed?

Residential backflow preventers typically are found on systems such as those for irrigating lawns, filling swimming pools and water features, and fire sprinkler systems. If your heat is supplied by radiators, the hot water boiler should have a preventer, as should a water softener. Toilets, bathtubs, sinks, hot water heaters and other standard plumbing fixtures do not require backflow preventers.

​Who can assist me in answering questions on the survey?

If you don't know an answer on the survey contact Public Works Department for assistance at 630-286-4750.

​​Where can I get a Backflow Prevention Survey? 

Surveys are typically mailed to local residents every two years. Survey can be located here.