- Shut off the water:
Shut down the water to your sprinkler system preferably before the pressure vacuum breaker. Most people take this as the main shut off for the irrigation. You can shut off the system here but if possible will want to shut the water off before the pressure vacuum breaker in order to remove the valve or insulate it and make sure there is no water going to it so it does not freeze.
- Remove the pressure vacuum breaker if possible:
Removing the pressure vacuum breaker if possible and storing it in a warm place will ensure that it does not get damaged over the winter. Some people put this in a shed or garage and it can still get damaged. Put the valve in the house if possible and this will save you from having to replace it. Instead of removing the pressure vacuum breaker you can drain and insulate it. Most hardware and home improvement stores sell insulated housings and bags that you can install over the pressure vacuum breaker to protect it from the cold. You can also buy insulation and insulate it yourself but make sure it is protected from the rain as well.
- Shut down your sprinkler timer:
Set the timer to the rain mode or off mode for the season. The timer will continue to send the signal to the sprinkler valves with or without water if it isn’t turned off so it is a good idea to save it from working all season by shutting it down. Turning it to the off position or rain setting retains any of the programming. Do not unplug the timer if you want to keep your same settings for next year’s watering.
- Drain down the system:
If you live a very cold climate you will have to drain down the system to remove any water in the lines that could potentially freeze. It is possible to drain down much of the system with auto drain valves that are usually installed in the lower portions of the sprinkler line. Also, many of the main shut off valves for sprinkler systems are stop and waste valves so when the pressure is off they will drain down much of the water in the system. Vacuuming out the water at each head and where you can will also help to get some of the remaining water.
By far the best method to drain the water in the sprinkler system is to have it professionally blown out with air. This is not an easy task to do by yourself because it requires specific equipment to do it properly. A low pressure high volume air compressor is needed to blow the water out of the system without damaging it. This type of compressor tends to be expensive and can be hard to find. Small air compressors can end up doing damage to the valves and heads because to compensate for the volume of air you will pump up the pressure which the valves may not be able to handle. Sometimes you can rent the necessary compressor at a local tool rental place so it might be worth looking into if you want to try doing it yourself.