Preparing Your Irrigation Systems for Winter – A Simple Guide

Properly winterising your irrigation system helps prevent frost damage, burst pipes, and costly repairs. This guide explains how to safely prepare and protect your sprinkler or drip irrigation system before freezing weather arrives.

Why Winterising Your Irrigation System Is Important

Winterising prevents freezing water from damaging pipes, valves, and sprinkler heads. If left full of water, your system may crack or split, causing leaks and failures. Winter preparation also protects your water supply and prevents frost damage to your home’s plumbing.

Steps to Prepare a Sprinkler or Irrigation System for Winter

1. Turn Off the Water Supply

• Shut off water at the main valve or garden tap.
• If using a pump and water tank, disconnect the pump, dry it, and store it indoors.
• Drain the tank and disconnect any mains or rainwater feeds.

2. Store Water Timers Indoors

• Remove tap timers and empty any water inside.
• Store them in a warm, dry location, ideally indoors rather than in a garage.
• Take out batteries to avoid corrosion during storage.
• Note: Manufacturers typically do not cover frost damage under warranty.

3. Drain the Irrigation System

When water freezes, it expands, which can split pipes and fittings. Remove as much water as possible:

• Remove stop ends to allow drainage.
• If your system includes drain valves, open them and leave them open for several days to ensure all water escapes.
• Close valves again once the system is dry.
• If no drain valves exist, use an air compressor to blow out the lines carefully. For safety, consider hiring a professional for this method.

Protecting Your System from Wildlife in Winter

While full disassembly isn’t needed, wildlife (especially foxes) may chew pipes or emitters to reach trapped water.

• Cap open pipe ends to stop bugs or debris from entering.
• Consider taping or covering emitters.
• If damage occurs, repair or replace affected parts before spring.

How to Winterise a Drip Irrigation System

1. Remove the timer and batteries, then store indoors.
2. Remove any tap accessories such as splitters or connectors.
3. Drain supply lines using manual or automatic drain valves.
4. Replace end caps after draining to prevent insects entering pipes.

Tip: Install automatic drain valves at the lowest point of your system for future convenience.

Temperature Guidelines and Watering Advice

How Cold Is Too Cold for Sprinklers?

Avoid using sprinklers when temperatures reach 0°C or below. If a hard freeze is expected, ensure all lines are drained or blown out.

When to Turn Off the Sprinkler System

Shut down your irrigation system before the first freeze. Avoid watering when temperatures are below 4°C, as cold air and wind chill can freeze grass blades.

Should You Water Before a Freeze?

A light watering before a freeze can help retain soil warmth and protect roots — but do not overwater.

• Helps soil retain heat.
• Insulates roots.
• Provides a protective moisture layer for foliage.

Should You Water Grass in Cold Weather?

• Water in the morning so moisture can soak in before nightfall.
• Avoid watering when frost is expected overnight.

How Often Should You Water the Lawn in Winter?

In winter, lawns only need about half an inch of water per week. In the UK, natural rainfall is usually sufficient, so manual irrigation is often unnecessary.