What Does It Mean to Winterize Your Sprinkler System?
Winterizing your irrigation or sprinkler system helps protect it from freezing temperatures. While the process can be as simple as shutting off the water supply and draining the system, the exact steps depend on the type of irrigation system you have.
Your irrigation system is made up of a network of pipes, valves and sprinkler heads. During freezing weather, any water left inside these components can freeze and expand, causing the components to crack or burst. The resulting damage can lead to costly repairs, water waste and delays in getting your lawn and landscape watered properly in the spring.
Considerations
Before winterizing your irrigation system, consider your location and the severity of your winter weather. In colder climates, plan to winterize before the first hard freeze, when nighttime temperatures are expected to remain below 32 degrees Fahrenheit for an extended period. Starting early helps reduce the risk of freeze damage if cold weather arrives sooner than expected.
In warmer climates, a complete winterization may not be necessary every year. However, if freezing temperatures are expected, shut off the irrigation system, drain exposed piping when possible and insulate above-ground backflow preventers, valves and other exposed components. Follow your irrigation system manufacturer's recommendations for your region.
How to Winterize Your Sprinkler System
The winterization process depends on the type of irrigation system you have. Some systems drain automatically, while others require manual draining and many underground systems should be cleared with compressed air. Always follow the manufacturer's instructions for your specific system.
Wear safety glasses throughout the winterization process. Pressurized water, compressed air and debris can cause serious eye injuries. Never stand over sprinkler heads or other pressurized components while draining or blowing out the system.
Automatic-Drain Method
Automatic-drain systems use valves that drain the irrigation lines after the water supply is turned off and pressure is relieved.
To winterize an automatic-drain system:
- Shut off the irrigation system's water supply.
- Activate one irrigation zone briefly from the controller or manually open a zone valve to relieve pressure in the system.
- Allow the automatic drain valves to empty the remaining water from the piping.
- If recommended by the manufacturer, loosen the solenoid or manual bleed screw on each valve to allow any trapped water to drain completely.
- Once the system has finished draining, retighten the solenoids or bleed screws.
Manual-Drain Method
Some irrigation systems include manual drain valves that must be opened to remove water from the pipes.
To manually drain your system:
- Shut off the irrigation system's water supply.
- Locate the manual drain valves at the ends and low points of the piping.
- Open each drain valve slowly and allow the water to drain completely before closing it.
- Drain the backflow preventer if it includes drain ports.
- After the system has drained, close all drain valves.
Blow-Out Method
The blow-out method uses compressed air to remove water from irrigation lines and is commonly used for underground sprinkler systems. Because improper use of compressed air can damage sprinkler components or cause injury, follow the manufacturer's instructions carefully.
To blow out your sprinkler system:
- Shut off both the water supply and the irrigation controller or power supply.
- Put on safety glasses and connect an air compressor to the irrigation system using the proper blow-out fitting or coupler.
- Do not force compressed air through the backflow preventer unless your system is specifically designed for it. Whenever possible, connect the compressor at the manufacturer's recommended connection downstream of the backflow device.
- Starting with the irrigation zone farthest from the air compressor connection, activate one irrigation zone at a time using the irrigation controller.
- Open the air compressor valve slowly and gradually increase airflow until water begins discharging from the sprinkler heads.
- Continue blowing air through the active zone until only a light mist is visible, then shut off the air and move to the next zone.
- Repeat the process for each irrigation zone until all zones have been cleared.
- Disconnect the air compressor and relieve any remaining pressure according to the manufacturer's instructions.
- After winterizing your system, set the irrigation controller to "Rain Mode" or "Off." This prevents the system from running during freezing weather while preserving your watering schedule for spring.
Avoid operating any irrigation zone on compressed air for more than about two minutes at a time or whatever recommended by the manufacturer. Running sprinkler heads dry for extended periods can damage gears, seals and other internal components.
Tips for Maintaining Your Sprinkler System
Winterizing your sprinkler system is important, but regular maintenance throughout the year can help keep it operating efficiently.
- Learn how much water your lawn and landscape need. To measure irrigation output, place several rain gauges, throughout each irrigation zone. Run the system through a normal watering cycle and compare the amount of water collected. This catch-can test helps you determine how long to run your irrigation system and whether water is being distributed evenly.
- Inspect sprinkler heads regularly for clogs, damage and proper alignment. Brown or dry spots in your lawn may indicate clogged nozzles, damaged sprinkler heads, low water pressure, leaks or misaligned sprinklers. Correcting these problems early can help prevent larger repairs later.
- After draining the system, protect exposed backflow preventers, valves and above-ground piping with insulated covers or other materials designed for freeze protection. Insulation helps reduce freeze damage but does not replace proper draining or blowing out the irrigation system.