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uk Home & property emergencies boiler leaking water • dripping boiler • boiler leak getting worse • water under boiler • puddle near boiler • wet around boiler pipes • central heating leak • combi boiler leaking • boiler pressure dropping • noisy boiler and leak • dripping from boiler bottom • leak near filling loop • water near electrics boiler • renting boiler leaking • landlord boiler repair urgent • gas boiler safety concern • possible carbon monoxide worry • heating stopped and leaking

What to do if…
your boiler or furnace is dripping water and the leak seems to be getting worse

Short answer

Switch the boiler/heating system off and keep water away from electrics, then get it assessed urgently by a Gas Safe registered engineer (or your landlord/agent if you rent).

Do not do these things

  • Do not keep restarting or “testing” the boiler while it’s leaking.
  • Do not open the boiler casing or try to tighten internal parts.
  • Do not touch plugs, switches, or the boiler electrics if the area is wet or you’re standing in water.
  • Do not ignore gas/CO warning signs (gas smell, soot marks, a CO alarm sounding, or people feeling suddenly unwell).

What to do now

  1. Turn the heating system off. Use the boiler’s off switch/controls first. If you can do it safely, turn it off at the fused spur (the wall switch near the boiler).
  2. If there’s any gas smell, a CO alarm is sounding, or anyone feels suddenly unwell (headache/dizziness/nausea):
    • Get everyone into fresh air immediately (outside if possible).
    • Do not use electrical switches on the way out.
    • Call the National Gas Emergency Service: 0800 111 999 from outside/away from the building.
    • Get medical advice promptly (NHS 111 for suspected CO symptoms; 999 if severe). Do not go back inside until you’ve been advised it’s safe.
  3. Stop water feeding the leak (only if you can do it confidently).
    • If you can see the filling loop and its valves, turn them to closed (often at 90° to the pipe).
    • If water appears to be coming from mains-fed plumbing (not just the boiler casing), and it’s safe to do so, use your main stopcock to limit further damage while you wait for help.
  4. Protect against electrical risk and damage.
    • Keep people and pets away from the wet area.
    • Put a bowl/tray and towels under the drip; mop up standing water.
    • If water is running toward sockets, wiring, or your consumer unit, switch off power at the consumer unit only if it’s safe and dry to do so. If it isn’t, step back and call for urgent help (landlord/agent/emergency electrician).
  5. Arrange urgent repair by the right person.
    • If you rent: report it to your landlord/agent as an urgent repair (heating/hot water, pipes/drains, gas installations and electrical wiring are generally their responsibility).
    • If you own: book a Gas Safe registered engineer. Tell them the leak is worsening and what you’ve already turned off (fused spur, filling loop, stopcock).
  6. Capture the basics (takes 60 seconds, helps speed the fix).
    • Photo/video of the leak and where it’s dripping from (wide shot + close-up).
    • Note any error code, unusual noises, and whether your system pressure is dropping quickly.

What can wait

  • You do not need to diagnose the cause right now (condensate, pressure relief discharge, pipe joint, internal component, etc.).
  • You do not need to decide on replacement vs repair today.
  • You do not need to drain the heating system or dismantle panels.

Important reassurance

Boilers can leak for reasons that look dramatic but are fixable. Your job in the first moments is to prevent water/electric shock risk and avoid making the fault worse by repeatedly running the system.

Scope note

These are first steps to stabilise the situation and reduce risk. A qualified professional still needs to inspect and repair the boiler and any affected electrics.

Important note

This is general safety information, not a diagnosis. If you smell gas, suspect carbon monoxide, or the leak is affecting electrics, treat it as urgent and get professional help.

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