Water Cross-Connections

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Water Cross ConnectionsCross-Connections

A "cross-connection" as defined by the Environmental Protection Agency, is any actual or potential connection between the public water supply and a source of contamination or pollution. More specifically, it is a physical link that allows potential backflow incidents; permanent or temporary piping arrangement which can allow your drinking water to be contaminated if a backflow condition occurs.

In the event of a backflow or backsiphonage event, such cross-connections constitute a hazard to the building occupants and can jeopardize the cleanliness and potability of the public water system.

Examples of Hazardous Cross-Connections

Cross-connections happen when a hose, pipe or a basin containing a substance other than drinking water is connected to a potable water distribution system. When this happens there is potential for backflow, or back siphonage.

Potentially hazardous cross-connections occurs every time someone:

  • Uses a garden hose sprayer to apply insecticides or herbicides to their lawn.
  • Places a hose in a bucket or pool.
  • Uses their garden hose to clear a stoppage in their sewer line.

There are many other potentially hazardous cross-connection scenarios. Please review the links below for more information or call or email us directly if you have any questions regarding cross-connection and backflow conditions.

Additional Cross-Connection information can be found at:

What is Backsiphonage?

A backsiphonage condition can occur whenever there is a lowered pressure between the potable and non-potable supply piping. For instance, during the demands imposed by fire fighting operation, or in the event of a water main break, the City water pressure may suddenly drop to a pressure that is lower than that of the non-potable system. This results in a partial vacuum being drawn on the non-potable system, and siphons the pollutants or contaminants into the potable water system.

What is Backpressure?

A backpressure condition occurs whenever an elevated pressure exists between the potable and non-potable source. These pressures can be imposed by the installation of pumps, which increase pressures above the City water supply pressure, thereby forcing non-potable water in the opposite direction of normal flow into the potable water line. Boilers or other equipment, which heat water causing thermal expansion and resulting in pressures in excess of the incoming water pressure, also can force non-potable water into the potable water piping system. 

What is a Cross-Connection Control Program?

A cross-connection control program is an organized, legally implemented and structured program to eliminate and contain the hazards to municipal potable water supply. These programs have been implemented and are typically passed by state or local law, and enforced by the local water supplier, such as the City of Dunedin.