The first thing to do is to freeze-proof the main shutoff valve for your irrigation system. Temporarily shut off the water supply then make sure that the valve itself is below the frost line, inside a heated room, or wrapped in appropriate insulation. If you don’t have a main shutoff valve for your irrigation system, then you’ll have to install one.
If you have an automatic system, then you will also need to temporarily shut off the controller (also known as the timer). Most controllers have what’s called a rain mode which shuts off all signals to the valves. An alternative to making use of the rain mode is to switch off all power to the controller. Be aware, however that if you do this, you’ll need to reprogram the controller when warm weather returns.
Gear-drive rotor sprinklers that are installed above ground need to have any water remaining in them drained out. If you don’t do this, they may freeze and rupture. If the water doesn’t drain out by itself, you’ll need to install a drain valve somewhere on the pipe that supplies the sprinkler so you can remove the water.
Also take stock of all pipes that are located above the ground, as these, too must also be insulated to protect against costly breakages. Insulating pipework is not as difficult as it sounds: you can purchase self-sticking foam insulating tape to wrap around the pipe or you can use foam insulating tubes. Be sure to also insulate above ground backflow preventers and valves if you don’t remove and store them.
