Backflow Prevention Installation

Protecting Your Drinking Water


Quality of drinking water is important to everyone and there are ways to keep your water supply safe. The “Protecting Your Drinking Water” article deals with cross connections associated with automatic sprinkler systems. This article also covers the installation of backflow prevention assemblies, the testing procedures required for a backflow assembly, and the training required of all testers for state certification.

Backflow Prevention Alternatives for Home Irrigation Systems (Irrigation Safety)


Irrigation systems make watering lawns and gardens easier and save time, but water that may be contaminated by weed killers and/or fertilizers can be back-siphoned (backflow) into your drinking water. Irrigation systems not protected by approved backflow prevention assemblies could endanger the health of a household, neighborhood, or community.

Please note that all irrigation systems - new or existing - must be equipped with an approved backflow prevention assembly. Only properly installed, state-approved backflow prevention assemblies meet the plumbing code and provide health protection for your family and neighbors. Your local water utility can give you a free list of state-approved assemblies and certified testers.

Freeze Protection


All backflow prevention assemblies installed above ground need to be protected from freezing. Recommendations are to install a drip tight shut off valve (ball valve) below ground an the inlet side of the assembly. Install a shut-off valve with drain (stop and waste valve) just above ground level so piping ahead of the assembly can be drained. Open all testcocks, and shut off valves on the backflow prevention assembly half way and leave open. A low point drain should also be installed on your irrigation system.

Note: ALL IRRIGATION SYSTEMS supplied by public water systems REQUIRE A PLUMBING PERMIT before installation. All piping and materials upstream of (before) the backflow prevention assembly must be of a type which is approved by the International Association of Plumbing and Mechanical Officials.

Additional Resources

Public works waterline equipment installation