PanicStation.org
UK USA
uk Home & property emergencies

What to do if…
your boiler or furnace is leaking water and the situation is getting worse

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy UK guide

Short answer

Turn the boiler off, keep water away from electrics, and arrange urgent help from a Gas Safe registered engineer, or your landlord or agent if you rent.

Do not do these things

  • Do not keep restarting or testing the boiler while it is leaking.
  • Do not open the boiler casing or try to tighten internal parts.
  • Do not touch plugs, switches, the fused spur, or the consumer unit if they are wet, your hands are wet, or you are standing in water.
  • Do not ignore a gas smell, soot marks, a carbon monoxide alarm, or people feeling suddenly unwell.
  • Do not use an engineer for gas work unless they are Gas Safe registered and qualified for the work.

What to do now

  1. Turn the heating system off. Use the boiler controls first. If the fused spur or wall switch is dry, your hands are dry, and you are not standing in water, turn the boiler off there too.

  2. If there is any gas smell, a carbon monoxide alarm is sounding, or anyone feels suddenly unwell with symptoms such as headache, dizziness, nausea, breathlessness, confusion, or chest pain:

    • Get everyone into fresh air immediately, outside if possible.
    • Do not use electrical switches on the way out.
    • Call the National Gas Emergency Service on 0800 111 999 from outside or away from the building.
    • Get medical advice. Use NHS 111 if symptoms are mild and you need advice; call 999 if anyone is very unwell, collapsed, confused, short of breath, has chest pain, or symptoms are severe.
    • Do not go back inside until you have been told it is safe.

  3. Limit the water only if you can do it safely and confidently.

    • If you can see the filling loop and its valves, turn the valves to closed, often at 90 degrees to the pipe.
    • If water appears to be coming from mains-fed plumbing rather than just a small drip from the boiler, use your main stopcock to limit further damage while you wait for help.
    • Do not force stiff valves.

  4. Reduce electrical risk and water damage.

    • Keep people and pets away from the wet area.
    • Put a bowl, tray, or towels under the drip if you can do this without touching electrics.
    • Mop up standing water if it is away from sockets, switches, wiring, and the consumer unit.
    • If water is running toward sockets, wiring, or the consumer unit, switch off power at the consumer unit only if it is safe and dry to do so. If it is not safe, step back and get urgent help.

  5. Arrange the right repair.

    • If you rent, report it to your landlord or agent as an urgent repair. Heating, hot water, gas installations, electrical wiring, pipes, and water systems are usually the landlord’s responsibility.
    • If you own the home, contact a Gas Safe registered engineer and say the boiler leak is getting worse.
    • Ask the engineer to confirm they are registered and qualified for the type of boiler work needed.

  6. Record the basics if it is safe and quick.

    • Take one wide photo and one close-up photo or short video of where the water is dripping.
    • Note any boiler error code, unusual noise, pressure-gauge change, and what you have turned off.
    • Keep these details for the engineer, landlord, agent, or insurer.

What can wait

  • You do not need to diagnose the cause now.
  • You do not need to decide today whether the boiler should be repaired or replaced.
  • You do not need to drain the heating system, remove panels, or investigate inside the boiler.
  • You do not need to clean everything up before making the urgent call if the leak is still getting worse.

Important reassurance

A worsening boiler leak can feel alarming, but the first job is simple: stop using the boiler, keep away from wet electrics, reduce the water if you can do so safely, and get the right help.

Scope note

These are first steps only to stabilise the situation and reduce immediate risk. Later decisions about repair, replacement, electrical inspection, tenancy repairs, or insurance may need specialist help.

Important note

This is general information, not legal, medical, electrical, gas-safety, insurance, or other professional advice. If you smell gas, suspect carbon monoxide, or water is affecting electrics, treat it as urgent and get professional help.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

Support us