Some leaks announce themselves; others soak quietly behind a wall or under a floor for months. Leak detection uses specialist kit to pinpoint a hidden leak without tearing the house apart on a hunch - saving you the cost and mess of digging in the wrong place.
A specialist leak-detection visit is usually £150-£400. Many home insurance policies include "trace and access" cover that pays for it.
Typical UK Prices
| Job | Typical price |
|---|---|
| Standard leak-detection visit | £150-£350 |
| Acoustic / thermal survey | £200-£400 |
| Tracer-gas detection | £250-£450 |
| Detection + report for insurer | £250-£450 |
| Access & repair (once found) | from £150 |
Signs of a Hidden Leak
- A water bill or meter that keeps climbing for no reason
- Damp patches, blistering paint or a musty smell with no obvious source
- Mould or peeling paint on a wall with no obvious cause
- Warm patches on the floor (a hidden hot-water pipe)
- The mains stopcock hisses, or the meter ticks with everything off
How Leak Detection Works
- Acoustic
- Sensitive microphones listen for the sound of water escaping under pressure - the workhorse method.
- Thermal imaging
- A camera spots the temperature difference a leak creates, especially useful for hot-water and heating leaks.
- Tracer gas
- A harmless gas is introduced into the pipe and detected where it escapes - precise for tricky, buried leaks.
- Moisture mapping
- Meters map how damp spreads through walls and floors to narrow down the source.
Will Insurance Pay?
- Many policies include "trace and access" - cover for finding the leak and getting to it
- Check your policy before you pay; the detection cost is often reimbursable
- Keep the report and invoice for any claim
- Sudden escape-of-water damage is usually covered; gradual seepage may not be
Before You Call
Turn everything off and watch the meter. If it still moves, water is escaping somewhere.
Where's the damp? Warm or cold? When did it start? It all helps the engineer zero in.
Why Not Just Dig?
The whole point of leak detection is to avoid guesswork. Without it, finding a hidden leak means lifting floors or opening walls where you think the problem is - and if you're wrong, you've made a mess and a bill for nothing. Detection equipment narrows the leak to a small area first, so any access work is targeted and minimal. On anything more than an obvious drip, it's almost always cheaper than digging blind.
Where Hidden Leaks Usually Start
Most concealed leaks come from a handful of spots: buried pipes under solid floors, joints chased into walls, and failed seals around baths and showers letting water track under tiles. Leaks on hot-water pipes are especially sneaky, because the warm water evaporates and shows up as damp or a musty smell rather than a visible pool.
What Happens Once It's Found
Detection and repair are usually two stages. Once the engineer pinpoints the leak, they cut a small, targeted access point, make the repair, and the surface goes back. Because the access is minimal, so is the making-good. Keep every invoice and the detection report - if you're claiming on trace-and-access cover, your insurer will want them.
Why Acting Fast Pays
A hidden leak rarely fixes itself - it just keeps soaking timber, plaster and insulation, and a small trace-and-fix today is far cheaper than replacing rotten joists and a ceiling in six months. Creeping damp readings, a rising water bill, or a stain that keeps spreading are all reasons to call sooner rather than wait and see. The detection itself is quick; it's the damage from leaving it that gets expensive.
Prices are typical 2026 UK ranges and vary by method and region. For general call-out rates see our emergency plumber cost guide, and if the trouble is underground rather than in the pipes, our CCTV drain survey guide covers that side. If water is pouring in and you can't stop it, get an emergency plumber on the way now.