How to drain your sprinkler system

Draining your sprinkler system diagram

Draining the backflow preventer is necessary to prevent damage of broken pipes and parts.

  1. Turn off your water supply valve for the sprinkler system at the Main Shut Off Valve A. This is generally in the mechanical room of your home. A 3/4″ copper pipe tees off for the sprinkler system on the up-leg of the main water line after the meter, but before it goes into the hot water heater.
  2. Open all inlet and outlet drain valves on the backflow preventer. B and E
  3. Turn inlet and outlet ball valve handles to a 45 degree angel position. C and D
  4. Open drain valve near water supply valve to drain water back from backflow preventer.
  5. Some systems have manual drains in valve boxes outside that also need to be opened to help gravity drain the system. Other systems are equipped with automatic drain valves.