How to Winterize Underground Sprinkler Systems

If the underground sprinkler system pipes freeze, they can burst and cause a lot of damage. This can be very expensive to fix. Fortunately, there are things you can do to winterize the underground sprinkler system to stop this from happening. You can winterize the sprinkler system in a few short steps.

1. Turn off the water that goes to the underground sprinkler system. Protect the shut off valve to the sprinkler system by making sure it is below the frost line, is inside a heated room that is above 32 degrees, or is insulated.


2. Turn off the sprinkler control system to ensure it doesn’t start up while you are working on it.


3. Remove the backflow preventer and the sprinkler valves. Drain all of the water from them and put them away for the winter.


4. Remove all of the sprinklers, make sure there is no water in them, and put them away for the winter.


5. Insulate the above ground piping for the sprinklers by putting foam insulation tubes around the pipes. You can also use insulation tape.


6. Use a wet/dry shop vacuum to siphon all of the water from the supply lines underground. Use the vacuum to suck out all of the water. Also vacuum the water from the sprinkler riser. Put the cap on the riser when you are finished. This process can take some time to complete, as there may be a lot of water in the supply lines. It is imperative that you get all of the water out of the lines.