Winter pipe bursts often start with water freezing in exposed or poorly protected pipework. Reducing the risk means insulating vulnerable pipes, planning for cold weather and knowing how to isolate the water quickly. If a pipe is already leaking, focus on safety and stopping the supply before investigating the damage.
Why do pipes burst during winter?
Water expands as it freezes. In a confined pipe, ice and the resulting pressure can damage the pipe or its joints. Leakage may become obvious during the thaw, so rising temperatures do not mean the risk has passed.
The most exposed locations are often outside the regularly heated rooms: roof spaces, garages, external walls and outbuildings. A warm living room does not demonstrate that every pipe elsewhere in the property is protected.
Freezing is not the only cause of leakage. If damage occurs without a convincing cold-weather connection, our guide to why pipes leak in London properties explains the wider investigation.
What should you check before the cold arrives?
Swipe across to read the table.
Choose insulation that suits the pipe size and exposure. WaterSafe advises protecting cold-water storage tanks at the top and sides, while avoiding loft insulation directly beneath them so warmth from below can reach the tank. Ask a plumber if the arrangement is unclear.
Where a separate outdoor isolation valve is fitted, the outside supply may be isolated and drained for winter. Do not dismantle fittings or assume an unidentified valve serves only the garden tap.
Insulation slows heat loss; it is not an unlimited guarantee against freezing. Check inaccessible or persistently cold areas with a professional rather than climbing into an unsafe loft or lifting floors yourself.
How should you prepare when going away?
Do not leave winter protection to chance. The Met Office recommends leaving heating on low when away and having someone check inside the property. Agree access and emergency contact details beforehand.
For a longer absence, ask a plumber whether water isolation and a properly planned drain-down are appropriate. Closing the stop tap alone does not remove water already in pipes or storage vessels.
Check your heating instructions and any insurer requirements for an unoccupied home. A boiler’s own frost setting may not protect remote pipework, so ask what your system actually covers. Avoid relying on a single universal thermostat setting for every property.
Do not place portable heaters in a loft to protect pipes. Northern Ireland’s government guidance specifically cautions against using electric, gas or paraffin heaters in roof spaces.
What if a tap stops flowing during a freeze?
A frozen pipe is one possibility, but a supply interruption or closed valve can produce similar symptoms. Check your water supplier’s service information and whether other outlets are affected. Do not force a tap or keep an appliance running without its required water supply.
If freezing is suspected, isolate the water and switch off the boiler using safe, normal controls. Contact a plumber if you cannot identify the affected section or it is inaccessible.
For a clearly identified, accessible pipe with no visible damage, the Met Office advises gentle thawing with a hot-water bottle or warm towels, with a nearby cold tap open to relieve pressure and the supply isolated. Never use a blowtorch, naked flame or boiling water. Avoid electrical heating devices near water.
Watch for leakage as thawing progresses. Stop if damage appears; do not restore the supply to a known damaged pipe.
What should you do if a pipe bursts?
- Isolate the incoming water: use the internal stop tap if you can reach it safely. Do not force a seized valve.
- Stop water heating: switch off the boiler and immersion heater using normal controls where safe.
- Keep clear of electrical hazards: do not touch wet sockets, appliances or switches.
- Limit damage safely: use towels or a container only where there is no electrical or ceiling-collapse risk.
- Call for help: explain the leak location and whether the water has been isolated.
After isolation, accessible taps can help drain domestic pipework where appropriate. This does not empty every tank or a sealed heating circuit. If water continues, tell the plumber; do not climb into the loft looking for more valves.
For an active escape of water, contact our emergency plumbing service. Our emergency plumbing checklist covers preparing for the visit. In a flat, notify the building manager and affected neighbours; tenants should also contact their landlord.
What needs checking after the repair?
Ask why the pipe failed and what protection is needed before the next freeze. Replacing the damaged section may not address neighbouring exposed pipes or a recurring draught.
Photograph damage where safe and contact your insurer about its reporting process. Have affected electrical equipment assessed before reuse, and arrange appropriate drying and inspection of wet building materials. Do not conceal damp areas simply because the visible leak has stopped.