The self draining valves drain slow so there isn’t much extra water used. They also claim the tubing they use can expand 14% and water expands 6% when it freezes, so even if the system isn’t fully drained it won’t be damaged if it freezes.Click to see full answer. Furthermore, how do I drain my sprinkler system? Manual Drain Valve Locate the manual drain valves situated downstream of each zone valve. Turn off the water supply by closing the main valve to the sprinkler system. Open all the manual drain valves for each zone in the system, and leave them open so that all the water drains from the pipes and sprinkler heads. Beside above, do I need to drain my irrigation system? 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. Subsequently, one may also ask, when should I drain my sprinkler system? As a general rule, you should winterize your system at least a week before the first freeze is expected. Your grass will survive without regular watering during that time, as the plants are already preparing for the dry winter season.When should I worry about sprinkler system freezing?Sprinkler pipes and other components are at risk of freezing and breaking when temperatures drop below 32 degrees Fahrenheit. Immediate damage can occur to exposed pipes and sprinkler equipment with the first freeze of winter.