Irrigation System Winterization Explained

Image result for winterizing irrigation lawn system

Every year, we get questions from our irrigation clients about how and when to winterize an irrigation system. The tasks seems daunting at first, especially when our crew comes to their property with specialized equipment and gear. Really though, winterization is a fairly simple procedure that many homeowners elect to do on their own. While we recommend that only those with experience in irrigation maintenance winterize their own systems, an explanation of what winterization is can be extremely helpful to all sprinkler system owners.

What is Winterization?

When your irrigation system is winterized, it is essentially shut-down and prepared for the winter months. Sprinklers are turned off and excess water is blown out of all pipes with pressurized air. This ensures that freezing temps won’t cause water to expand in irrigation pipes, which could lead to the pipes becoming damaged or ruptured. Thus, winterizations are normally done before the onset of freezing temps, which, depending on which climate zone you live in, could fall anywhere from late September to late November.

How Winterization Works

First, your irrigation’s water supply needs to be shut-off. To do this, the irrigation system’s shut off valve must be activated. The shut off valve will likely be inside in a basement or utility room where the other water controls are.

Then, (for automatic systems) the systems controller must be shut-down. This can be done by shutting off signals to individual valves and turning off “zones” one-by-one, or the controller can be turned off entirely, which may save energy during the winter. If you’re attempting this yourself, see your controller’s manual for specific instructions.

Once that’s taken care of, water in the backflow device is drained. In some cases, the device can be deconstructed and stored for the winter. In more temperate climates, the backflow can be left alone or simply insulated to protect it from deep freezes. It’s essential that all excess water is removed from the backflow—backflows are expensive to replace or repair.

Along with the backflow, all pipes must be drained. This can be done a few different ways: manual drain, automatic drain, and blow-out method. Blow-out method is the most effective, but also the most dangerous. It should not be attempted by anyone who does not have irrigation system maintenance experience. For more information on manual and automatic draining, visit this site:

If the system is blown out, an irrigation tech will clear the system using a large air compressor (50-125 cubic feet per minute). The compressor is attached to the main water line via a coupling or hose bib. Before compressed air is blown through the system, the backflow’s isolation valves are closed to ensure that pressurized air is not shot through the backflow. Zones will generally be blown out starting with the farthest zone from the compressor and working up. Air is blown into each zone until water is done exiting the heads, at which point the zone is completely dry.

Once all zones are dry, isolation valves on the backflow are turned to a 45 degree angle (1/2 open) and the system is considered winterized until it is turned back on again in the spring. Now, your system is ready for the winter, and your water bills are probably going to be a little bit cheaper for a couple months. Hallelujah!


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