Frozen pipe

What has stopped flowing?

Use the pattern you already noticed: one exposed cold branch, several cold outlets, hot-only loss or an appliance/boiler error. Freezing is plausible in a cold exposed area, but supplier interruptions and closed/restricted valves are alternatives. Check your own supplier’s current information before assuming a whole-home loss is an indoor frozen pipe.

When gentle thawing is suitable

Read all the conditions and stopping points before starting. This is damage limitation and gentle warming, not a pipe repair. Do not apply the action to an unknown supply, an inaccessible section, a boiler condensate pipe or any heating/hot-water route.

• Use this only if the affected pipe and outlet are positively identified as a cold mains-fed branch, the suspected frozen section is fully exposed at reachable height, the route is dry and safe, and there is no visible split, leak or electrical exposure. Otherwise stop and call a plumber.
• Close only the positively identified conventional private inside mains stop tap clockwise by hand until it closes normally. Do not force it or operate shared, external, stiff or unfamiliar valves; stored supplies and heating circuits may remain live.
• Open the affected normal cold tap to provide an escape path, only where the outlet can be watched and has no visible drainage blockage. Do not leave it unattended or allow water to collect in the basin.
• Remove only loose accessible pipe lagging and move nearby loose possessions if safe; do not cut coverings or disturb fixed pipework, joints or building surfaces.
• Apply a wrapped hot-water bottle or warm towel gently to the exposed cold pipe, starting at the end nearest the tap and working back along the accessible section. Do not use boiling-water pouring, flames, electrical heat, force or rapid heating.
• Stay present and watch for water escaping or collecting, visible splits or unsafe conditions. Stop immediately for any leak or overflow; close the affected tap if its normal control remains dry and safe, keep the mains valve closed and seek plumbing help.
• When gentle warming has finished, close the affected tap normally and inspect the whole treated exposed section and joints from a dry, safe position. Any dampness, split, suspected hidden or still-frozen section, or uncertainty means keep the known private valve closed and arrange a plumber. Returning residual flow alone is not proof of complete thaw.
• Only if the entire suspected section is exposed, dry, confidently thawed and free of any other uncertainty, gently reopen the same known private inside stop tap using its normal operation, without force. Stay present and watch the treated pipe and joints as supply returns. If water escapes, close that same valve again if safely reachable, keep clear of wet electrics and obtain plumbing help. If normal cold service returns without leakage, continue watching for any leak; do not assume returned flow rules out other frozen sections.
• If thawing does not resolve the visible freeze, or you cannot confirm the complete section and supply, stop rather than increase heat or operate other equipment; arrange professional assessment.

What to do when thawing is unsuitable

• Record cold weather timing, affected outlets and already-visible frost or leakage from a dry safe position; do not deliberately run water to locate a frozen section.
• Check your own supplier’s interruption information and ask whether nearby homes already report a similar loss; do not assume all cold-weather supply loss is an indoor freeze.
• Report known recent valve/work changes without reopening a valve closed for a leak or unfinished work.
• For hidden, inaccessible, hot/heating/condensate or uncertain pipework contact the appropriate plumber/heating maintainer. For escaping water keep clear and use only the separate safe known-private-stop-tap action if applicable.

If you cannot identify a safe private inside stop tap, do not experiment with outside or shared controls. A pipe hidden in a wall or loft is not made suitable for DIY by seeing frost nearby. Arrange assessment rather than climbing, opening the building or increasing heat.

Leaks during thaw need prompt action

Leakage can appear as temperatures rise even without deliberate thawing. Keep clear of spreading water and affected electrics. The known private inside valve may limit incoming mains water, but it does not necessarily stop stored water or a heating circuit. A plumber needs to check the damaged route; a heating-system concern needs the appropriate heating maintainer.

Record when water stopped, the outlets affected, the visible pipe/location and any safe thawing already attempted. Give this to the plumber or landlord/building manager. If a supplier interruption is plausible, ask the supplier what help or supply checks are available; no response time or repair responsibility is guaranteed.

Thawing and repairing are different jobs

No directly matched all-in thaw/repair price is quoted. Ask whether the call-out includes diagnosis and thawing, what happens if a split is found, and whether labour, parts, VAT, hidden access, making good and a return visit are included. Check your policy before assuming frozen-pipe damage is covered.

Questions about frozen pipes