Living in Colorado means that the winter season brings us beautiful white landscapes and ice formations. It also means that the snow won’t melt for days on end and where the frost level extends below the depth of the installed piping. That also means that you need to take measures to protect your irrigation system from freezing in order to avoid costly repairs in the spring.
Draining some water out of the system is not enough because the remaining water can freeze, expand and crack the PVC piping from fitting to fitting. If your system has polyethylene pipe, although this type of pipe is more flexible and can expand under pressure, you are taking a great risk by leaving water inside as it could freeze and rupture the pipe walls. It is simply not prudent to leave water to freeze in the backflow assembly as it will damage the internal components and crack the brass body.