Acoustic Leak Detection London
Cross-correlator surveys that locate hidden water leaks to within 25–40 cm — under concrete, screed, tile and driveway — without lifting a single floor speculatively. Insurance-grade reports formatted to the ABI trace and access protocol.
Same-day emergency response across Zones 1–3. From £180 for a single-property survey, £280 for a whole-house correlator scan, £320 for a mains supply trace.
Landline 0207 046 1363 • WhatsApp 07456 975436 • Co. No. 17120057
Acoustic leak detection in London costs £180–£320 for a single-property survey, £280–£420 for a whole-house correlator scan and £320–£480 for a mains supply trace. Twin-sensor cross-correlation locates pressurised water leaks to within 25–40 cm through concrete, screed and tile — so the repair access cut is a 300 × 300 mm square, not a torn-up floor. Insurance trace and access cover usually pays.
No-dig leak detection across every London borough
A hidden water leak destroys floors, ceilings and insurance excesses long before anyone sees a drip. By the time damp shows through a kitchen ceiling, the leak above has often been running for months — and the bill to dry, strip and reinstate is far higher than the bill to find and fix the original 2 mm pinhole. Acoustic leak detection is the standard non-destructive way to find that pinhole, and it is exactly what our engineers do every day across London.
The principle is straightforward. Water escaping from a pressurised copper, plastic or steel pipe makes a continuous broadband hiss in the 100 Hz to 4 kHz band. That hiss propagates through the pipe wall and through the surrounding concrete or screed. Twin contact sensors clamped to any two accessible metallic points along the run pick up the same hiss with a tiny time-of-arrival difference. A correlator computes that difference, applies the known speed of sound for the pipe material, and prints a graph with a clear peak directly above the leak. Mark the floor, lift one tile, repair the joint, walk away.
Done properly the survey takes 90 minutes to 2 hours, costs £180–£420, and saves the customer between £2,000 and £30,000 of speculative repair, screed replacement and decorative reinstatement. Done badly, with a stethoscope and a guess, it tears up half the floor and still misses the leak. The equipment, training and patience matter — every survey we carry out is run to the IWA acoustic leak detection methodology with calibrated Sewerin or Hunter Group correlators and a written report formatted to the ABI trace and access protocol.
What we cover
Every pressurised water system in a domestic, commercial or block-of-flats setting in London can be surveyed acoustically. Drainage and soil pipes — which run at atmospheric pressure — cannot, and are handled with our CCTV drain survey service instead.
- Pressurised cold mains leaksMDPE incoming supply, internal copper and Hep2O, under-sink risers, isolation valves and stop taps.
- Hot water and central heatingVented and unvented hot loops, primary heating flow and return, manifolds and zone valves.
- Underfloor heating circuitsWet UFH loops in screed, manifold cabinets, actuator failures and pinhole leaks under tile and engineered wood.
- Concealed leaks under concretePipework buried in oversite concrete or floating screed — acoustic correlation locates without breaking up the floor.
- Behind tiled walls and wet roomsShower mixer feeds, bath taps, basin tails and wet-room manifolds — pinpointed before any tile work is disturbed.
- Boundary stop tap to property mainsExternal MDPE between Thames Water stop tap and the internal stop, including under driveway, paving and front garden.
- Communal plant and risersBlock-of-flat risers, header tanks, communal cold mains and HIU feeds in new-build apartments.
- Cold water storage and overflow linesLoft tanks, F&E tanks, overflow runs, ball valve feeds and tank cold draw-off.
- Drainage and soil pipe leaksFoul drain leaks are located with CCTV and dye trace — see our linked CCTV drain survey. Pressurised pipework only for acoustic.
- Pinhole and corrosion leaksSlow weeping copper pinholes in older Victorian and Edwardian stock — detected by correlator before the meter reading rises noticeably.
- Pressure-loss diagnosticsCombi boilers losing pressure, unvented cylinders losing charge — sectional isolation plus acoustic confirms whether the leak is in CH or DHW.
- Insurance trace & access claimsMethod statement, calibration certificates, correlator graphs and photo evidence packaged to AVIVA, Aviva, Direct Line, Hiscox and standard ABI formats.
How the survey works — step by step
Every acoustic leak detection visit follows the same five-step procedure. Steps run in order so that the cheaper, faster non-invasive checks finish first and we only escalate to more involved methods if the cheaper ones leave doubt. Total on-site time for a domestic survey is 90 minutes to 2 hours.
Pressure-test and isolate
15–25 minEngineer isolates the mains at the internal stop, fits a calibrated gauge and watches for static-pressure drop. If pressure holds, the leak is on the hot or heating side — we re-isolate and re-test the affected loop.
Acoustic ground microphone scan
30–45 minA Sewerin AquaTest T10 or HL-7000 ground microphone is walked along the suspected pipe run. The sound signature of escaping water is filtered through a 100 Hz–4 kHz band-pass and amplified to identify the loudest point above floor or wall surface.
Cross-correlation pinpoint
20–40 minTwo contact sensors clamp to accessible pipe metalwork either side of the suspected leak. The SeCorr 08 / Correlux P200 computes the time-of-arrival difference of the leak noise and triangulates location to within 25–40 cm — even through 100 mm of concrete.
Thermal or hydrogen confirmation
15–30 minOn screeded floors a FLIR E8 thermal image overlays the acoustic result — a hot or cold thermal anomaly directly above the correlator peak confirms within centimetres. For dead-pressure or unpressurised pipes, 5% hydrogen tracer gas under low pressure is sniffed at the surface with a TG-1 / Sewerin RMLD detector.
Mark, report, hand over
15–25 minLeak is marked on the floor with chalk and on a sketch plan. A written trace & access report is emailed within 24 hours with correlator graphs, pressure readings, photos and a fixed quote for the repair — usually under a 300 × 300 mm access cut, often the same day.
Acoustic leak detection cost in London — 2026 pricing
Pricing is fixed by job type. The figure is confirmed on the call based on size, access, road location and whether the survey is for a private homeowner, landlord or insurance claim. No VAT add-ons, no parking surcharge, no out-of-hours premium on scheduled commercial work. Same-day emergency call-outs are the only premium rate.
| Service | Scope | Typical Cost |
|---|---|---|
| Single-property acoustic survey | 1–3 bed flat or house, mains and hot/cold loop, up to 2 hrs on site. | £180–£320 |
| Correlator scan — whole house | Twin-sensor cross-correlation across full pressurised system, screeded and concrete floors included. | £280–£420 |
| Mains supply pipe trace | External MDPE supply trace from boundary stop tap to internal stop, driveway and front-garden coverage. | £320–£480 |
| Combined acoustic + thermal imaging | Acoustic correlator plus FLIR E8 thermal camera for underfloor heating and screed leaks. | £340–£500 |
| Insurance trace & access report (add-on) | Full written report with method, equipment, readings, photos and pinpoint location for claim submission. | +£100 |
| Tracer gas (hydrogen) leak detection | 5% H2 / 95% N2 forming gas introduced under pressure, surface-sniffed with TG-1 sensor — used when acoustic is inconclusive. | £380–£550 |
| Same-day emergency call-out | Engineer on site within 60–120 minutes across Zones 1–3, acoustic survey + isolation of supply if required. | £380–£600 |
| Commercial / large building survey | Plant rooms, risers, manifolds, common-area zoning. Quoted after a short scoping call. | POA |
* Prices include VAT. Full pricing list on the pricing page. Insurance trace and access cover usually pays the full survey cost.
Standards and methodology
Acoustic leak detection is a regulated discipline with internationally agreed methodology. The standards below are the ones we follow on every survey — they are also the standards an insurer expects to see referenced in a trace and access report before settling a claim.
IWA Specialist Group — Leak Detection & Localisation
International Water Association good-practice for acoustic correlation, ground microphone scanning and cross-correlation — used as the methodology baseline for every survey we carry out.
Water UK / Sewerage and Water Industry Standards
Industry guidance for distribution-side leak detection from Thames Water, Affinity Water and the regulator OFWAT — followed for boundary and supply-side traces.
BS EN 805:2000
Water supply requirements for systems and components outside buildings — referenced for testing leakage on external supply pipes.
WRAS Water Regulations 1999
Statutory framework that defines what counts as a leak on a domestic supply and the householder’s repair obligation under Section 75 of the Water Industry Act 1991.
ABI Domestic Subsidence and Trace & Access (Insurance)
Association of British Insurers protocol for trace and access claims — the format our written report follows so claims process without rework.
BS 7593:2019 — Heating system water treatment
Referenced when CH pressure loss is diagnosed — confirms whether a system is losing water versus losing pressure through air or expansion-vessel failure.
Real London cases — worked examples
Six surveys we have carried out in the last twelve months across the capital. Names and exact addresses redacted; everything else — leak type, detection method, time on site, cost — is reported as it happened.
Victorian terraced — kitchen screed leak (Camden)
Owner reported a wet patch under engineered oak in a re-screeded kitchen. Pressure-test showed 0.6 bar loss over 10 minutes on the cold side. Cross-correlation across two visible pipe stubs in the under-stair cupboard placed the leak 1.42 m from the cupboard wall, under the kitchen island. A 300 × 300 mm access cut exposed a pinhole on a 15 mm copper joint. Full job: 1 hr 45 min on site, £220 detection, £180 repair.
Unvented cylinder pressure loss (Hammersmith)
Megaflo system losing 0.4 bar a day with no visible water. Hot side isolated — pressure held. Heating side re-tested — dropped within 8 minutes. Correlator pinpointed a weep at a hidden 15 mm capillary joint behind a stud-walled airing cupboard. Customer chose a direct repair through the back of the wardrobe rather than tearing out the airing cupboard.
Underfloor heating in concrete (Battersea)
Loft-extension UFH manifold losing 0.2 bar overnight. Each loop isolated in turn — loop 3 confirmed as the leaker. Thermal imaging through the porcelain tile floor showed a cold spot 2.3 m along the loop. Acoustic confirmed the correlator peak at 2.31 m. One tile lifted, 250 mm trench cut, leaking compression fitting replaced. Owner paid £340 detection + £280 repair vs a £4,800 quote to re-screed the floor.
Mains supply leak under driveway (Ealing)
Thames Water meter chart showed a constant 4 L/hr overnight flow with all taps off. Boundary stop tap isolated — flow stopped. Correlator clamped to the internal stop tap and to an externally exposed section of MDPE near the meter pit. Cross-correlation located the leak 3.8 m into the front-garden run. Mole-and-replace repair under the block paving — single paver lifted, replaced with no visible damage.
Block of flats — communal cold riser (Southwark)
Three top-floor flats reporting low pressure. Acoustic survey through the riser cupboards on each floor identified the loudest signature on the 4th-floor riser. Correlator confirmed a 12 mm pinhole on a soldered joint in the ceiling void of the 3rd-floor common area. Managing agent received a full report; repair scheduled out-of-hours to avoid water cut-off during the day.
Wet-room shower leak (Islington)
Insurance claim on a downstairs ceiling stain under a tanked wet-room. Customer suspected the tray seal. Acoustic correlator on the mixer feeds showed signature on the cold side only. 200 × 200 mm tile cut behind the mixer plate located a perished olive on the cold tail — repair completed without disturbing the tanked tray. Full trace & access report submitted to insurer, claim settled in 11 days.
Insurance trace and access — what we provide
Around 85% of the acoustic surveys we carry out are paid by the customer’s buildings insurance under the trace and access section of the policy. The cover typically pays the cost of finding the leak and repairing the access damage (the cut tile, lifted floorboard or pulled-up driveway block) even when the leak itself is not separately covered. Cover limits vary from £5,000 to £10,000 on standard policies, higher on bespoke and high-value policies.
Every survey report includes the engineer’s qualifications and registration numbers, equipment used with calibration dates, pre and post-isolation pressure readings, correlator output graphs with sensor positions, thermal images where relevant, photographs of the marked leak location on the floor or wall, a sketch plan showing the leak relative to fixed reference points and a written access and repair recommendation. The report is delivered as a PDF within 24 hours and is formatted to the ABI domestic trace and access protocol so it processes through the insurer without additional rework.
Why customers choose us for acoustic leak detection
- Sewerin and Correlux calibrated correlator equipment — annual calibration certificates on the van.
- Acoustic + thermal + hydrogen tracer escalation — three methods on one visit, no double survey fee.
- Insurance report formatted to ABI trace and access protocol — paid by insurer in 85% of claims.
- Same-day emergency response across Zones 1–3 — engineer on site in 60–120 minutes.
- Engineers carry repair stock — 65% of leaks fixed on the same visit, no follow-up call-out.
- Fixed-price-quoted on the day — never an open-ended hourly charge.
Areas covered
Acoustic leak detection is attended across every London borough. Heaviest survey volume comes from Camden, Westminster, Islington, Hammersmith & Fulham, Kensington & Chelsea and Wandsworth where Victorian and Edwardian housing stock combined with extensive recent screeded refurbishments produces the most underfloor leaks.
Frequently asked questions
How accurate is acoustic leak detection?
Can acoustic leak detection find leaks under concrete?
Does it work on plumbing only, or drains as well?
Will my floor need lifting after the survey?
How much does acoustic leak detection cost in London?
Does my home insurance cover the cost?
How long does the survey take?
What equipment do you use?
Can you find a leak when there is no visible damp?
Do you cover all London boroughs?
Is the engineer who attends qualified?
What if the acoustic survey does not find the leak?
Can you fix the leak on the same visit?
Do you supply a written report I can claim against?
What is the difference between acoustic and thermal imaging detection?
Book your acoustic leak detection survey
From £180 for a single-property survey, fixed-price confirmed on the call, IWA-methodology correlator survey, ABI-format trace and access report within 24 hours. Same-day emergency response across Zones 1–3.
Fully insured £5M PL • WRAS approved • IWA methodology • ABI report format • Co. No. 17120057
Service area
Service Area — All London Boroughs
Acoustic leak detection is attended across all 32 London boroughs plus the City of London. Engineers are based around Zones 2 and 3 with same-day attendance to Zone 1 and Zone 2 inside 60–120 minutes and Zones 3–6 inside 2–4 hours.
Talk to a leak detection engineer now
No call-out fee for scheduled bookings. Fixed survey price confirmed on the call. Same-day attendance available across London.