Cross Connection Surveys December 2015
In an effort to protect the Village’s drinking water system from potential contamination, the Village has contracted Backflow Solutions, Inc. to conduct an audit of our drinking water system to identify potential sources of contamination. Conducting this survey is a requirement of the Illinois Environmental Protection Agency, and is intended to identify and correct any potential sources of contamination before such an event should occur.

A backflow event is one in which water or other substances are drawn into the Village’s water distribution system through a cross connection, creating the potential for contamination. The Village can control the quality of water in its distribution system up to the point where it enters the customer’s home or business. However, once the water has passed that point and has entered the interior plumbing of a building, the Village no longer has control over that water and it cannot be returned. Any path in which water may return to the Village’s distribution system is considered a cross connection, or a potential source of contamination. Backflow prevention devices are required to protect the public water supply from such potential sources of contamination.

Cross Connection and Backflow Prevention Frequently Asked Questions

1. What is backflow?

Backflow is the reverse flow of water or other substances through a cross connection into the treated drinking water distribution system. There are two types of backflow: backpressure and backsiphonage. Backpressure happens when the pressure of the contaminant source exceeds the positive pressure in the water distribution main. An example would be when a drinking water supply main has a connection to a hot water boiler system that is not protected by an approved and functioning backflow preventer. If pressure in the boiler system increases to where it exceeds the pressure in the water distribution system, backflow from the boiler to the drinking water supply system may occur. Backsiphonage is caused by a negative pressure (vacuum or partial vacuum) in the water distribution system. This situation is similar in effect to the sipping of water through a straw. Negative pressure in the drinking water system can happen because of a water main break or when a hydrant is used for fire fighting.

2. What is a Cross Connection?

A cross connection is a link between a potable water system and a non-potable water system. Typical cross connections within residential properties involve auxiliary water systems, heating & cooling systems and irrigation systems. Backflow can occur through any of these cross-connections.

3. What causes Backflow?

Backflow can be caused by a sudden drop in the water pressure in a public water main, which can create a sub-atmospheric condition. For example, if a drop in pressure occurs while a hose is in a bucket of dirty water, that water could be drawn back into the public water system, potentially contaminating the water for other users. A drop in pressure could be caused by a variety of things, including a water main break, a fire requiring water suppression, or the loss of power at a water pumping station.

4. What are the Hazards?

A backflow incident can cause any substance that can come into contact with water to backflow into the public water system contaminating the drinking water. The potential list of possible contaminants is unlimited. Throughout the United States, there are hundreds of documented incidents and probably thousands of undocumented cases. Once in the distribution system, it is impossible to determine the fate of the contaminant due to many variables such as the chemical and physical properties of the contaminant, the point of entry, and pressure and flow within the system.

5. Can Backflow be prevented?

Yes it can. Backflow can be controlled by installing a backflow prevention assembly where cross-connections exist and cannot otherwise be eliminated. These devices are installed at the primary point of entry of the water service or on the particular plumbing device that needs backflow protection and, when properly maintained, should prevent a backflow from occurring.

6. What are some examples of Backflow prevention devices?

Backflows due to cross connections are serious plumbing problems. However, backflow can be controlled by the use of proper protection devices. The following are three examples:

Hose Bibb Vacuum Breaker

Hose Bibb 2

At your home, each outside spigot with a threaded connection should have a Hose-Bibb vacuum breaker installed. These are simple, inexpensive devices that can be purchased at any plumbing or hardware store for about $10. Installation is as easy as attaching your garden hose.

Dual Check with Vent

Duel Check 2

This device consists of two independent check valves with a vent chamber located between the valves. This device is generally utilized in connections to hot water heating systems.

Reduced Pressure Zone (RPZ)

Reduced Pressure 2
This device consists of two independent check valves with a pressure chamber located between the valves. This device is generally utilized in connections to swimming pools and irrigation systems.

7. I received a survey in the mail from Backflow Solutions, Inc. What should I do next?

Simply fill out the information requested to the best of your knowledge, and return the postage paid postcard to BSI. Alternatively, you may file your survey report online at:

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