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Leak detection in London costs £150 to £450 for most surveys: £150 to £300 for a basic acoustic survey on a pressurised pipe, and £250 to £450 for a full survey using acoustic, thermal imaging and moisture mapping with a written report. Tracer gas adds £80 to £200, and a same-day emergency trace is £350 to £550.
| Job | London low | London typical | London high | UK typical | What moves the price |
|---|---|---|---|---|---|
| Thermal imaging survey, heating or hot-water pipes | £150 | £200 | £250 | One to two hours; shows warm pipes and the wet patches a leak leaves under floors and behind plaster, but not a leak on a cold pipe; from £180 at one London firm | |
| Basic acoustic survey, pressurised water or heating pipe | £150 | £225 | £300 | £160 | One to three hours; ground microphones follow the noise of water escaping under pressure; UK guides put a standard trace at £115 to £234 |
| Tracer gas test, buried or cold pipe that makes no noise | £200 | £280 | £350 | Two to three hours; a hydrogen and nitrogen mix is put into the drained pipe and picked up where it escapes; £80 to £200 as an add-on to an acoustic survey | |
| Full survey, acoustic plus thermal plus moisture mapping, with written report | £250 | £350 | £450 | Two to four hours, up to £500 for a large house; the report with photos and a marked floor plan is what the insurer asks for; a standalone insurance report is £50 to £120 | |
| Underfloor heating leak survey | £250 | £375 | £500 | Each loop is pressure-tested separately, then thermal imaging with the floor warm, so it is slower than a survey of ordinary pipework | |
| Emergency same-day trace | £350 | £450 | £550 | For water coming through a ceiling or a supply pipe the stopcock cannot isolate; a planned find-and-fix visit starts at about £280 |
The signs are a damp patch that dries and comes back, a warm spot on a floor, a boiler that loses pressure every few days, or a water meter that keeps turning with every tap off. It is urgent when water is coming through a ceiling or the stopcock does not stop it; a planned survey a day or two later costs about half the emergency price.
On the day the engineer asks what you have seen, pressure-tests the heating and the mains separately to see which is losing water, then follows the pipe route with ground microphones, a thermal camera and a moisture meter. Tracer gas goes in only where a buried or cold pipe makes no noise. The leak is marked to within a few centimetres, so only one patch of floor or plaster is opened, and you get a written report with photos for the insurer. Most surveys take one to three hours at a fixed price agreed before the visit; many firms repair on the same visit from about £280.
Most home insurance includes trace and access cover, typically £5,000 to £10,000, which pays for the survey and making good once a leak is confirmed.
Prices last checked: September 2026. Based on published London rates and quotes seen through PROS AI London requests, checked September 2026.
£150 to £450 for most surveys, against a UK average of about £160. A basic acoustic survey on a pressurised pipe is £150 to £300, thermal imaging £150 to £250, a tracer gas test £200 to £350 and a full survey with all three methods and a written report £250 to £450. A same-day emergency trace is £350 to £550. Most London firms quote a fixed price before the visit rather than an hourly rate.
Turn off every tap and appliance, read the water meter, wait 30 minutes and read it again; if it has moved, water is leaving the supply pipe somewhere. A boiler that needs topping up every few days is losing water from the heating circuit. Other signs are a damp patch that comes back after drying, a warm area of floor, a musty smell, or a water bill well above the previous quarter.
Acoustic detection, £150 to £300, uses ground microphones to hear water escaping under pressure and works on mains and heating pipes. Thermal imaging, £150 to £250, shows warm pipes and the cold, wet patches a leak leaves, so it suits heating and hot-water leaks under floors. Tracer gas, £200 to £350, fills a drained pipe with a hydrogen and nitrogen mix and picks it up where it escapes; it is for buried or cold pipes that make no noise.
Usually, if a leak is found. Most buildings policies include trace and access cover, typically £5,000 to £10,000, which pays for the survey and for opening up and making good, though not always for the pipe repair itself. Check the policy before you book, keep the invoice, and ask the engineer for the written report with photos; a standalone insurance report is £50 to £120 if it is not included.
One to three hours for a single method, two to four for a full survey of a house. The engineer pressure-tests the heating and the mains separately, follows the pipe route with microphones, a thermal camera and a moisture meter, and marks the leak to within a few centimetres. Fixed prices are agreed before the visit; a planned find-and-fix visit starts at about £280, and a same-day emergency trace at £350.
Written by PROS AI editorial team.
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