How to winterize a lawn irrigation system

Updated September 2026 · Lawn Care AI team

Identify your system’s drainage method, arrange any required blow-out and complete the shutdown checks before freezing weather.

What you need

Your irrigation layout and manuals, access to the dedicated water shut-off, a zone list, labels and a phone for reference photos. Arrange a winterization appointment if the system requires a blow-out or its drainage design is unknown.

Step by step

1. Identify the system. Locate and photograph the dedicated irrigation shut-off, backflow assembly, drain points, pump and controller model. Confirm whether the installation uses manual drains, automatic drains or compressed-air winterization. Do not assume water will drain just because the sprinklers stop.
2. Record existing problems. Before shutdown, note leaking valves, damaged heads and zones needing spring repair. Give the contractor a complete zone list, including drip lines and any separate garden circuits. Tell them about flow meters, check valves and a water pump.
3. Stop scheduled watering and isolate the supply. Set the controller to its manufacturer’s off or winter mode and close the irrigation water supply as directed for the installation. Use the dedicated irrigation shut-off, not an unidentified household valve. Keep pumps from starting against an empty system using their prescribed shutdown procedure.
4. Drain using the verified method. For a documented manual-drain system, follow the installation instructions for pressure release and each low-point drain. Automatic drains do not guarantee the backflow assembly, check-valve heads or above-ground pipework are empty. If you cannot account for these components, have the system serviced.
5. Have any required blow-out completed. The contractor must match airflow and pressure to the lowest-rated component, use the correct connection and handle each zone. A compressor’s maximum pressure is not a target setting. Do not send compressed air through the backflow device or pump, and do not stand over pressurized components.
6. Check separate components. Follow the exact backflow and pump manuals for draining and final valve positions. Ask how flow sensors and drip filters or regulators were protected. Do not copy a generic handle position from a different assembly. Disconnect and drain portable hoses and hose-end timers as their manuals direct.
7. Leave the system in its specified winter state. Confirm controller power instructions rather than simply unplugging everything. Protect exposed parts as directed without blocking vents or drain outlets. Insulation alone does not remove water or guarantee freeze protection.
8. Record completion. Save the shutdown date, contractor details, final settings and unresolved repairs. Label the system as winterized so no one restarts watering during a warm spell.

Before the next watering season

Arrange spring startup after local freeze risk has passed. Have required backflow testing completed and restore valve positions using the system procedure. Check each zone for leaks and coverage before enabling a regular schedule. If freezing has already occurred, do not force frozen valves or attempt a blow-out through ice; have the system assessed.

Common questions

Sources and further guidance

• Hunter Industries — Winterization procedures
• Rain Bird — Irrigation winterization
• Rain Bird — Winterizing a controller