Can Freezing Weather Cause Drain Blockages or Pipe Bursts?

Freezing winter weather can wreak havoc on your home’s plumbing and drainage systems. In the UK, where winters are usually mild, it’s easy to be caught off guard by a sudden cold snap. But even just a few sub-zero nights can freeze standing water or vulnerable pipework—leading to blocked drains, burst pipes, and expensive damage. One burst pipe alone can cost upwards of £7,500 in repairs and restoration.

In this guide, we’ll cover:

• How freezing weather causes blocked drains and burst pipes

• Early warning signs to watch for

• Step-by-step prevention tips

• What to do if your pipes freeze or burst

  
  

How Freezing Weather Causes Drain Blockages

Ice Build-Up from Standing Water

Water trapped in outdoor drains, U-bends, or gully traps can freeze solid. As more water arrives and freezes, these small ice patches grow into full-scale blockages that prevent drainage.

Debris Turns to Ice

Leaves, silt, or cooking fats can trap moisture in pipes. In cold temperatures, this trapped water turns into solid ice, clogging your drainage system. In kitchens, fats flushed down the sink can congeal faster in winter, becoming rock-hard obstructions.

Frozen Gullies and External Drains

Outdoor drainage points—manholes, gullies, and downpipe outlets—are especially prone to freezing. When they ice over, water backs up around the property, increasing the risk of flooding and slippery surfaces.

Action Tip: Clear outdoor drains and gutters regularly, and never pour cooking fats down the sink—especially in cold weather.

How Freezing Weather Causes Pipes to Burst

Expansion Pressure

When water freezes, it expands by around 9%, exerting pressures over 2,000 psi—easily enough to split plastic or metal pipes from within.

Thaw-Time Failures

Pipes often burst after the freeze ends. As the ice plug melts, water suddenly rushes through and escapes via any cracks formed during the freeze. This is when damage typically becomes visible.

At-Risk Pipes

The most vulnerable are those in unheated areas: lofts, garages, underfloor crawl spaces, and external walls. Outdoor taps and poorly insulated boiler condensate pipes are common problem areas. Dripping taps also freeze more readily due to slow water movement.

UK Winter Plumbing Risks

• Sudden temperature drops across the UK can freeze pipes quickly

• Outdoor taps and boiler condensate pipes freeze easily without insulation

• Older homes may lack pipe lagging or wall insulation

• Even coastal or southern areas can see sub-zero nights

Did You Know? In the 2018 "Beast from the East," over 200,000 UK households lost water due to burst pipes—after just a few days of extreme cold.

Warning Signs of Frozen Pipes or Blocked Drains

Act fast if you notice any of the following:

• No water or very weak flow from taps

• Toilets not refilling properly

• Slow-draining sinks, baths, or outdoor gullies

• Foul smells from plugholes or manholes

• Gurgling or banging noises in your plumbing

• Visible frost or condensation on exposed pipes

• Damp patches, ceiling bulges, or mystery puddles indoors

Early intervention can prevent a major flood or system failure.

How to Prevent Winter Drain Blockages and Burst Pipes

1. Insulate Pipes and Outdoor Taps

• Use foam pipe lagging in lofts, garages, and unheated areas

• Fit insulation jackets on cold water tanks

• Cover outdoor taps with insulated tap covers

• Wrap boiler condensate pipes with weatherproof lagging

2. Keep Heating On

• Maintain at least 14°C inside the home—even overnight

• Use timers or smart thermostats with frost protection

• Keep internal doors open to allow warm air to circulate

• If away for several days, either drain the system or keep heating on low

3. Clear Gutters and Outdoor Drains

• Regularly remove leaves and debris

• Use guards or covers to protect external drains

• After freezing nights, check for pooling water near the house

4. Avoid Fats and Grease in Sinks

• Don’t pour oil, fat, or gravy down the drain

• Scrape plates and pans before washing

• Use hot water and detergent to rinse greasy dishes

5. Fix Leaks and Drips Early

• Repair dripping taps before cold weather hits

• Small leaks can freeze into blockages and escalate into pipe bursts

6. Drain the System If You’re Away

• If the house will be unoccupied, turn off the stopcock and drain pipes

• Alternatively, keep heating on low and ask someone to check in

7. Know Your Stopcock

• Locate your home’s water shut-off (usually under the kitchen sink)

• Ensure it’s accessible and operational

• Save the number of a trusted emergency plumber in case of trouble

What to Do If Pipes Freeze or Burst

Turn Off the Stopcock Immediately

Cut the water supply to limit flooding and reduce pressure in frozen pipes.

Open All Taps

This allows trapped water and pressure to escape safely as things thaw.

Thaw Pipes Slowly

Use a hairdryer on low, warm towels, or hot water bottles. Never use flames or boiling water—they can crack pipes or start fires.

Contain Leaks

Move valuables, use buckets and towels, and turn off electricity near water-affected areas.

Call a Professional

A qualified emergency plumber can locate the problem, make safe repairs, and check for wider damage.

Document the Damage

Take photos and contact your insurer if repairs are substantial.

Conclusion

Freezing weather can absolutely cause drains to block and pipes to burst—but most of the damage is avoidable. By insulating your pipes, maintaining indoor warmth, keeping drains clear, and acting quickly at the first sign of trouble, you can save yourself thousands in repairs and keep your home safe all winter.

With the right preparation and vigilance, even the harshest UK winter doesn’t have to catch you—or your plumbing—off guard.

If you're ever in doubt, then it’s time to contact a professional. GSB drainage offers expert drain unblocking services across Southampton and the surrounding areas. Get in touch today for a free quote.