How to Winterize a Drip Irrigation System: 5 Steps to Success

Turn the master shutoff valve on your mainline to stop the flow of water to your system.

Take apart the head assembly. Confirm there isn’t water remaining in the backflow preventer, the filter, and the pressure regulator. If you have a timer, remove the batteries to prevent corrosion. Once complete, pack and store these components indoors, where they’ll be less likely to freeze.

Some drip systems use outdoor hoses connected to faucets to work. If you have this type of system, unscrew the hose and make sure it’s drained of water. Store the hose away from freezing conditions until winter is over.

If you have a manual drain system, open the end caps on all the emitters and let the water drain out. Walk through the whole system, lifting the tubing and the fittings at any low points to flush out any trapped water. 

If your type of system features automatic valves, manually confirm that all valves are open and then run the controller through its normal cycle to remove any remaining water. Re-open all valves to prevent water from gathering inside while it sits idle.

Drip irrigation isn’t under the same pressure as a sprinkler system, and water is less likely to linger in delicate components that it can damage when frozen. That’s why it’s a largely optional step for most home drip systems. However, if your irrigation system combines drip lines and sprinklers, we highly recommend a blowout. It’s also a good idea if your manual drip lines are sloped in a way that makes gravity-based drainage difficult.

If you don’t have experience using an air compressor, consider hiring a sprinkler winterization pro to complete this task. Highly pressurized air can easily cause serious injury. If this is a task you’d prefer to DIY, rent an air compressor from your local equipment lender or hardware store. Wear ANSI-rated eye protection to shield yourself from the pressurized air and any debris it may set loose. 

Slowly turn the shutoff valve back to the open position. Attach the compressor hose to the threaded opening on the mainline and ensure the connection is tight; use pliers or a wrench if necessary. Set the air compressor to 30 pounds per square inch (psi). Slowly increase the pressure as needed and stop once air comes out of the emitters. 

Once the lines have fully drained, put all the end caps back on the emitters, but leave them loose—this will allow any excess water to drain throughout the winter while preventing wandering insects from damaging the tubing. Just don’t forget to tighten the end caps before you start the system up again next spring. Lastly, cap the female end of the threaded swivel adapter removed from the faucet assembly during step two.