We just bought a house with a fairly simple sprinkler system. There is only one zone and no timer. You turn the system on and off with a valve off the main water line in the basement. On the outside of the house, a PVC pipe comes out through the wall and is connected to a plastic hose that goes into the ground and out to the sprinkler heads. The hose is connected to the pipe with a hose clamp. My question is: When I'm ready to shut down the system for the winter. could I just disconnect the hose from the PVC pipe and leave it open? Would the open hose allow the water to expand and keep the ice in the lines from cracking the pipes in the ground? I'm not trying to be cheap - I'm just wondering if it's necessary to have someone come in just to blow the water out of the lines. Thanks.