How to Find a Hidden Leak Under Floors — UK Method
A hidden pipe leak costs UK homeowners an average £2,900 by the time it's found. Here is the diagnostic order UK leak detection engineers follow.
Step-by-step method
1. Confirm there is a leak
Turn off all taps. Note the water meter reading. Wait 60 minutes with no consumption. Any change = leak.
2. Isolate hot vs cold
Close the boiler cold feed and rising main separately. Repeat meter test to narrow down.
3. Thermal imaging camera
Hire (£40/day Screwfix) or hire leak detection company. Hot pipe leak shows as red streak on cooler floor.
4. Acoustic leak detection
Professional service — geophone or Aquascope. £180–£350 for a callout, finds leak within 100mm accuracy.
5. Tracer gas as last resort
Hydrogen/nitrogen mix pumped into pipe, sniffer detects gas escape. £250–£450 professional service.
Frequently asked questions
Does home insurance cover leak detection?+
Yes — most 'trace and access' cover pays for detection and reinstatement, up to a limit (typically £5,000).
Signs of a hidden leak?+
Unexplained water meter movement, damp patches, high water bill, mould in unusual spots, warm spots on ground floor (hot leak), unexpected boiler pressure loss.