Hidden Leak — What to Do Right Now
Hidden leaks don't drip on the floor — they show up as boiler pressure loss, a jumped water bill, or a warm patch on a floor with no heating in it. Left alone, they cause structural damage before you see any water.
Make it safe — before anything else
The meter test is your first fast diagnosis
30 minutes, everything off, before / after reading. It costs nothing and confirms if you have a mains-side leak.
Track boiler pressure daily for a week
Note the cold pressure each morning. A properly sealed system loses pressure very slowly. Weekly drops = leak.
Trust your nose
Musty smells or new mould in a room with no visible water means moisture behind a wall or under a floor.
Don't cut anything speculatively
Guessing where the leak is and cutting into a wall costs you money and doesn't find it. Non-invasive detection first, then a targeted small hole.
What Kevin (our AI) will check first
Message Kevin and he'll ask exactly these questions before we send an engineer, so we bring the right parts on the first van.
- Water-meter reading before and after a 30-minute isolation test?
- Boiler cold pressure and how often you top it up?
- Any warm spots on solid floors, or unexplained damp patches on walls?
- Has the water bill increased without lifestyle change?
- Any recent building work, drilling, or new appliance install upstream of the suspected area?
Common causes of a hidden leak
Underfloor mains leak
Pinhole in a copper mains pipe buried under a solid floor. Often shows as a warm patch (if hot) or via the meter test (if cold). Located with acoustic listening or thermal camera.
Central-heating leak under a floor
Pinhole in a copper or plastic heating pipe. Boiler keeps losing pressure. Thermal camera finds it easily because the pipe is hot.
Pinhole radiator leak into carpet
Slow drip into carpet under a rad, evaporating before you see it. Musty smell, damp underlay.
External supply pipe leak in the garden
Between the water-authority stop-tap and the house. Meter runs, but no wet inside — often shows as a green stripe in the lawn.
Failed shower-tray or wet-room membrane
Water tracks through the substrate and shows up rooms away. Not a burst — a slow, chronic failure.
Honest cost band — why we won't quote blind
Typical
£220 – £360 for a leak detection visit with a written report
Complex
Complex multi-method jobs, or excavation to access an external supply leak: £360 – £950.
Detection is separate from repair — we quote both so your insurer can approve trace-and-access separately. £50 diagnostic refunded if we can't locate the source.
Fixed £50 diagnostic
Flat fee. No hourly meter running.
Fair quote or refund
Transparent pricing — refunded if we don't fix it.
Vetted UK engineers
DBS-checked, insured, real reviews.
AI-triaged in seconds
KJ chats first so the right engineer arrives.
Related emergencies
See all in the emergency plumbing hub — or the leaks & water damage hub.
Areas we cover for hidden leak
Same-day across Greater Manchester and Rochdale.
Hidden leak — FAQs
Dealing with a hidden leak? Chat with Kevin now
Real triage in seconds. £50 diagnostic visit — refunded if we don't fix it.
Related hubs: emergency plumbing, leaks & water damage, all services.
Chat with Kevin about Hidden leak