Every year, before the first freeze, the ritual of irrigation “blow out” becomes the priority for all irrigation systems in regions located where the frost level extends below the depth of installed piping.
Even if you have drained the water out of your irrigation system, some water remains and can freeze and crack the PVC piping. Although polyethylene pipe is more flexible and can expand under pressure, water left inside can freeze and rupture the pipe walls. Freezing water in the backflow assembly will damage the internal components and can crack the brass body.
To minimize the risk of freeze damage, you’ll need to winterize your irrigation system. In areas where winterization is mandatory, irrigation systems are installed using one of three types of water removal: manual drain, auto drain, or blowout. If you don’t know your system type, it is best to use the blowout method.