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Leak detection and repair

A non-invasive leak detection survey costs £250 to £600 and finds the leak without taking a floor up. Most buildings insurance policies cover this under a trace and access clause, which is worth checking before paying for it yourself.

Describe your job

A floorboard lifted over a leaking pipe, with a damp patch above and a thermal camera

What this covers

Typical price. £250 to £600 for a detection survey

What the job covers

  • Tracing leaks under floors and behind walls
  • Thermal imaging and acoustic detection
  • Repairing failed joints and pinholes
  • Shower tray and seal leaks that look like plumbing
  • Reports for insurance trace and access claims

What is involved

Finding a leak is a different skill from fixing one. A specialist uses thermal imaging to see the temperature difference a leaking hot pipe creates through a floor, acoustic equipment to hear the escape of pressurised water, tracer gas pushed into a drained pipe and sniffed at the surface, and moisture meters to map how far the water has travelled. That last point matters, because water runs along joists and appears in a room that has nothing to do with the failed pipe.

A fair share of suspected plumbing leaks turn out to have another source. A shower tray whose seal has failed, a bath with a perished waste washer, grout that has opened up in a wet area, or a roof or window defect will all produce a wet ceiling below. A survey that starts by ruling those out saves lifting a floor for nothing.

On heating systems, the sign to watch is pressure. A sealed system that needs topping up every few weeks is losing water somewhere, and the loss is often at a radiator valve gland or a compression joint under a floor. On mains supply, a leak between the meter and the house shows as a meter that turns with every tap in the house shut off, and that section of pipe is usually the homeowner's responsibility.

Water staining spreading down a wall from a hidden leak

Tracing leaks under floors and behind walls, one of the jobs a leak detection specialist is hired for.

Choosing someone for the job

Check your buildings insurance for trace and access cover before booking, and ask the firm whether they produce insurer-ready reports. Ask which detection methods they carry, because thermal imaging alone will not find a cold water leak in an uninsulated void. Ask whether the quoted price includes the repair or detection only.

Worth reading first:

Common questions

Does insurance pay for leak detection?

Most buildings policies include trace and access cover, typically to a few thousand pounds, which pays to find the leak and make good afterwards. The repair to the pipe itself is usually excluded.

How do I know if I have a hidden leak?

Turn every tap and appliance off and watch the water meter for half an hour. If it moves, water is going somewhere. On a heating system, pressure that falls week after week is the equivalent sign.

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