As summer fades, falling leaves and cooling temperatures are a good signal it’s time to shut down your irrigation system and prepare for the cold ahead. Expensive pipes and components are at risk of damage when the temperature dips below 32°.

Parts above ground are at the most risk because freezing temps may cause immediate damage. Prolonged freezing temps (3 or more days) can cause soil temperature to dip and cause further damage to underground pipes. You will be unaware of burst or damaged parts until the following spring, when you turn on the water again and notice leaks.

Taking the time this fall to properly shut down your irrigation, will prevent future costly repairs. Following our 4 steps to winterizing your irrigation system will protect your investment.

Please note that many systems are similar; however, some components vary. Even though assembly and parts vary, shut down procedures are typically the same.

Sprinkler head spraying water in a irrigation zone

Step 1: Turn Off Main Valve

Locate your irrigation main valve. This is often close to the backflow prevention device. There are typically two kinds of main valves; the first looks like a spigot handle which is a gate valve. The second looks like a t-handle called a ball valve (shown in picture).

Expert Tip: If you turn this off and get complaints from the household that there is no running water, one of two things could have happened. (1) You either turned off the main water or (2) someone mistakenly connected irrigation lines to the main water line. If it is the latter you need to contact an irrigation specialist.

Irrigation winterization showing a main valve shut off

Step 2: Turn Off Backflow Device

Turn the handle attached to your backflow preventer, perpendicular to the device. This is typically the off position.

Diagram photo of backflow device and handle

Step 3: Open Outlet Drain

Connected to your backflow device, there will be an outlet side drain. This is the one to open.

Backflow testing

Step 4 (Optional): Open & Close Valves

This step is optional if you plan on using compressed air to remove all remaining water in your system (highly recommended). Systematically run through the system, opening and closing each valve. This can be done manually from each sprinkler head or from your clock. Doing this relieves excessive water pressure from the system, protecting lines and heads during the compressed air step.

The video shows how to open and close an irrigation valve.

Step 5: Blow Out Water

Hook up a high volume-low pressure air compressor to your backflow prevention device test port. Turn on the air compressor to charge main-line, this will expel all remaining water.

winterizing your sprinkler system

Step 6: Open Valves

Slowly open valves one at a time to blow remaining water out of the opened zone. After all water is expelled from the valve, proceed to the the next and repeat process until all zones have been worked through.

Step 7: Open Drains

Leave all drains to the open position. All drains should remain this way until you start up your system the following spring.

Expert Tip: Remember to close drains when you start your system up in spring, otherwise all the water will be flowing wildly through your system.