How to Winterize Your Drip Irrigation System

Winterizing your drip system is very important in areas prone to freezing or during long periods of inactivity. It is the process of removing water from the system that can otherwise damage the drip tubing and components during freezing cold weather. When water freezes in tubing, it expands, creating pressure that can burst tubing, damage fittings, and other valuable components. Even brief freezes, such as an unexpected cold snap in warmer regions, can damage an unprotected irrigation system. So if you haven't already considered winterizing, now is the time to cross this task off your "to-do" list. It's basically a few-step process to protect your system's components and help them last longer.

Why Winterizing the Drip Irrigation System Matters

Freezing temperatures and severe winter storms can damage irrigation systems. The expansion of freezing water generates enormous pressure in the drip irrigation parts. The most vulnerable components of your drip system are the fittings, emitters, thin-walled tubing, and filters. These components are not designed to withstand the internal pressure caused by ice formation, so the force of expansion can damage pipes, valves, and fittings.

Many homeowners discover damage only when they restart their systems in the spring. By then, winter's freeze-thaw cycles have done enough damage. Water seeps into small cracks, freezes again, and spreads the damage with each cold spell.

Even irrigation systems in areas with mild winters aren't immune. A brief cold burst can catch unprotected systems off guard and cause just as much damage as prolonged freezing temperatures.

Here is the damage freezing temperatures can cause to your drip system.

Expansion and Contraction

When temperatures rise and fall significantly, the tubing and system connections naturally expand and contract. This frequent movement can loosen fittings, weaken joints, and cause small cracks that can grow into bigger issues.

Frozen Water Expansion

Any water left in the drip tubing, emitters, or filters can freeze and expand, potentially causing cracks, ruptures, and leaks.

Damaged Parts

Above-ground components such as valves, timers, and backflow preventers are highly vulnerable to freezing conditions. The damage to these parts can lead to costly replacements.

Structural Shifts

Ice, snow, and frost can displace tubing and disrupt fitting connections, potentially leading to leaks or a non-functional system in the coming spring.

Clogging and Build-Up

Debris left in the system during winter can harden and clog drip emitters. Residue buildup reduces system efficiency when it is turned back on.

How to Winterize Drip Irrigation

Let's look at the steps to winterize your system and prevent damage.

Flush the System

The first step is to flush your irrigation system with pressurized water to remove debris or residue. You can also flush it with chlorine water to clean the system and to kill and remove any algae growth. If doing so, flush again with water to remove the chlorine.

Turn Off Water Supply

Locate the main water valve for your drip irrigation system and turn it off to prevent new water from entering the system during freezing weather. The shutoff valve is usually located at the outdoor spigot or the point where your system connects to the home's water supply. Test a few emitters to ensure that the water flow has completely stopped. Once the water supply is turned off, no water should drip from the emitters.

Drain and Remove All Water from System

Open manual valves and remove all the end fittings or flush caps from the lowest discharge points in the system to drain the water from the tubing. These valves are specifically installed to remove water during maintenance. If your irrigation system does not have flush caps, remove the end caps from mainlines to drain all the water.

Walk across your irrigation tubing and gently elevate the fitting sections to direct trapped water towards the drainage points. Pay special attention to the lowest spots where water usually collects, as these are the most vulnerable areas to freeze damage.

It is recommended to install Flush Valves at low points in the lines to help with draining the system. When the system is turned off, the flush valves open to drain water trapped in the lines.

Tip: Give several hours for complete drainage, especially if your system covers a large area. Gravity does most of the work, but slow drainage provides better protection than rushing the process.

Disconnect and Store Drip System Components

Remove the timer, filter, pressure regulator, and backflow preventer at the start of the system and bring them inside. Drain these components, clean them thoroughly, and store them in a dry, protected place where they won't get damaged from freezing.

If you have exposed above-ground tubing, cover it with a good layer of mulch to protect it from the cold.

Blow Out the Lines

If you suspect there is still water in the lines or other components, use compressed air to blow it out. This is an effective and time-saving method. Remember to remove end fittings first to avoid damaging the system.

Seal the Open Lines

Once the lines are completely drained, replace all end fittings. Leave the end caps loose on the tubing to allow for drainage throughout the winter. Don't tighten these caps as the main winterization goal is protection.

The start of the system, from where you removed the faucet assembly, should also be sealed off. Use a female hose plug to seal the female hose start fitting. You may also use a plastic bag or another barrier to cover the system's opening.

Tip: Never leave irrigation lines open, as debris, insects, and other creatures might hide in them.

Protect Remaining Components

In cold climates, it is always best to wrap exposed above-ground drip components like valves and backflow preventers with foam insulation, weatherproof tape. This protection can prevent damage to system components from frost and freezing. If your drip irrigation system has control valves, remove them and store them indoors. They cannot tolerate freezing.

Mark Your System Location

If you live in a snow-covered area, mark the system's locations with stakes. Use markers and flaglines to label where lines and emitters are present. This prevents you from accidentally damaging the buried components during winter activities and makes the spring restart easier.

Winterization Tip: Use row covers to protect your plants from frost damage, and extend the growing season.

Plan for Spring Startup

• The slow winter season provides a great opportunity to plan for the garden changes for the next year. Consider which plants, containers, or raised beds you want to add or relocate, and how these changes will affect your irrigation needs.
• Inspect your drip irrigation system in early spring before the last frost date. This inspection allows you to discover and repair any winter damage before the new growing season begins.
• Check for any damage that may have occurred over the winter despite all the precautions. Look for damaged emitters, cracked pipes, or loose connections, and address them promptly before restarting the system. Additionally, make sure to tighten all end caps and inspect the connections for leaks.
• Replace the batteries in your electronic timers with new alkaline batteries and replace any damaged components. Freezing weather can drain stored batteries, even when stored inside.
• Test your irrigation system at low pressure first by slowly turning on the water and checking each zone individually. This will help you identify leaks. Once you know everything is working smoothly, increase to normal operating pressure. Your careful winter care of the garden irrigation system should result in a system ready for another successful season of efficient watering.

The Bottom Line

Preparing a drip irrigation system for freezing winters is important to prevent system damage. Be proactive and protect your drip system from cold weather with the steps outlined above. These winterization methods will protect your garden irrigation system, your investment, and your property. You risk losing your significant investment if you let the system components freeze and burst. Less than an hour of winter care for the garden irrigation system is usually all it takes to keep it clean, efficient, and ready for use in the spring.