Backflow Hazards

Cross Connections
If you have a lawn irrigation system or are thinking of getting one, then you need to learn about backflow. Backflow refers to the flow from a possible source of contamination back into the drinking water system.

Backflow can be a health hazard for your family or other water consumers if contaminated water enters your water supply plumbing and is used for drinking, cooking, or bathing. Cross-connection between your lawn irrigation system and water supply system is prohibited by law. It is your responsibility to protect your water supply plumbing and the public water system from backflow contamination.

Backflow Causes
Backflow can occur when a cross-connection is created and a pressure reversal (either backsiphonage or backpressure) takes place in the water piping. Lawn irrigation systems have the potential to be a backflow hazard. Fertilizers, pesticides, and animal feces could be drawn into your water supply plumbing from the sprinkler nozzles of the lawn irrigation system.

To protect against the possibility of backflow contamination, the Oconomowoc Water Department requires all lawn irrigation systems to be equipped with approved, testable backflow prevention devices. If your system has a device installed, it must be tested annually and the test results sent to the Water Department.

If your system does not have a device installed, you must have one installed. The installation and testing is to be done by personnel certified to test backflow preventers. The irrigation contractors should be familiar with this and should be doing it each year as part of turning on your system for the summer. There are a number of state certified testers of backflow prevention devices.

Other Common Backflow Hazards

In addition to lawn irrigation systems, there are other common backflow hazards. For example, a garden hose submerged in a bucket of soapy water or other cleaning compounds, in a laundry basin, or in a swimming pool could backsiphon into your water supply. Do not submerge hoses or place them where they could be submerged.

Consider using hose bib vacuum breakers on garden hose connections in the basement, laundry room, and outside. They are inexpensive and usually available at your local hardware store.