Cold weather is on its way, so now is a great time to winterize your sprinkler and irrigation system. Follow these steps to ensure that your pipes don’t crack when your world freezes. Not familiar with your sprinkler system? We recommend hiring a service to "blow out" and winterize your system (details in step #9).
Note: If you’re unsure about certain terms in this to-do, use the pictures at the bottom as a reference. It's best to consult your owner's manual for specific locations of parts.
For both cold and temperate climates. These steps should be taken for all sprinkler systems that will have to withstand freezing temperatures this winter. Even if you only get one freeze a year, it’s important to follow these steps! A single freeze can still damage your sprinkler system.
Locate and turn off the main shut-off valve to the sprinkler supply line. This will usually be located underground (below the frost line) and inside of a heated room, but for warmer climates it may be outside. If it’s a ball valve, turn the handle so that it's perpendicular to the supply line (it is "on" if it is parallel to the supply line). If it’s a gate valve, it will look like a small wheel. Turn the wheel clockwise as many times as you can so that it’s completely closed. If you have a petcock (a round valve that looks like a large toothpaste cap) near your main shut-off valve, open that all the way.
If you have an automatic sprinkler system, turn off the controller. Most systems have a setting – often called “rain mode” – that will stop the sprinklers from activating, but will retain all of your programming information. However, if your controller has analog dials it probably uses more power than a system with a digital display, and it may be worth turning off completely to save electricity during the winter.
If your system has above-ground, gear-drive rotor sprinklers, the water needs to be drained out of them so that they don’t break during a freeze. For some systems, the rotors will drain automatically when you shut down the controller. If they don’t, the easiest thing to do is remove the rotors and either shake them out and replace them, or store them inside until spring.
If any of your system’s ground pipes, valves or backflow preventers are above ground, they should be insulated. You can use foam insulating tape for all of these areas, which costs around $10 at your local hardware store. Be thorough with this step, because if you do it properly once, you probably won’t have to do it again in future years. Note: Make sure you don’t block any air vents or drain outlets when you apply the tape!
For cold climates. If you live in a temperate climate, you’re done. Go relax. Enjoy a brew. If you live in a cold climate – meaning you have to shovel snow during the winter, or that ice hangs out for more than a few days without melting – you need to take a few more winterizing steps.
If you have a system with a manual drain, open your manual drain valve – this is usually a gate valve that you need to turn counter-clockwise. Warning: Open this valve slowly because there may be pressure built up in the pipes. Most excess water will then flow out of the low points of your system. Then, open either your “boiler drain valve” or the cap on your “stop and waste valve” (different systems have one or the other) which will drain more water. Finally, open all test cocks and check valves in case there is any water remaining. Close all of these valves once they’re fully drained. Note: Your petcock should stay open.
If your system has automatic drain valves, open them by turning off your main shut-off valve and then activating a sprinkler. The change in pressure will open the valves automatically, and the lowest parts of your system will drain. Then, repeat the rest of step 7. Note: Some systems have both manual and automatic drains, so you may have to combine steps 7-8.
If your climate sees extremely cold winters, or you don't feel comfortable fooling with your sprinkler system, consider having your sprinkler system “blown out” rather than draining it yourself. This is not a DIY project! It involves compressed air and complex machinery, so we recommend hiring a professional to do this for you. Prices will vary depending on your location and the size of the system, but it will generally cost $75-$100 to have your sprinklers blown out.