Water Pipe Leak Under Your Garden or Driveway?
We locate MDPE supply pipe leaks without excavating — acoustic survey to within 25–40 cm, then a single small access point for the repair. Mole-and-replace repairs for block paving driveways leave pavers undisturbed.
Detection surveys from £280. Same-day response across Zones 1–3. No find no fee — if we can't locate the leak, you pay nothing.
Landline 0207 046 1363 • WhatsApp 07456 975436 • Co. No. 17120057
- Thames Water meter ticking overnight with all taps off
- Water bill significantly higher than usual
- Wet or boggy patch in garden with no recent rainfall
- Drop in water pressure inside the property
- Thames Water has contacted you about a leak notification
- Damp patches appearing on concrete or driveway surface
One of these is usually enough to warrant a pressure test. Call 0207 046 1363 for a same-day survey.
Which pipe is leaking — and whose responsibility is it?
The supply pipe — also called the communication pipe extension or private supply pipe — runs from the Thames Water boundary stop tap at the edge of your property, under your front garden, path, driveway or side return, and connects to the internal stop tap inside your home. In most London properties this is a straight run of 2–15 metres, depending on how far the building sits from the street.
On properties plumbed in the last 30 years this pipe is almost always blue MDPE (medium-density polyethylene) — flexible, corrosion-resistant, and connectable with push-fit or compression fittings. On pre-1970 London properties, particularly terraced and semi-detached Victorian stock, this run is often old lead, which corrodes internally and eventually cracks or splits at joints.
This entire pipe run is the homeowner's responsibility, not Thames Water's. The boundary stop tap is the legal dividing line. Everything from that tap into your property — the pipe itself, the joints, the internal stop tap — is yours to maintain and repair under Section 75 of the Water Industry Act 1991. Thames Water's responsibility ends at the edge of your property boundary.
How we find the leak without digging
Every supply pipe leak survey follows the same five-step sequence. Steps 1 and 2 are free non-destructive scans. Step 3 is the correlator pinpoint. Step 4 is a confirmation method for plastic pipe with no metallic reference. Step 5 is the mark and quote. Total time on site is 2–3 hours, and the only thing we break ground on at that stage is the chalk mark.
Pressure test at both stop taps
20 minEngineer fits a calibrated pressure gauge at the boundary stop tap and the internal stop. Static pressure is watched over 10 minutes on each side of the isolation. If pressure drops with the boundary tap isolated, the leak is confirmed on the private supply run between the two stops — not on the Thames Water main, and not on the internal plumbing.
Acoustic ground microphone scan
30–45 minA Sewerin AquaTest T10 or Vivax HL-7000 ground microphone is walked along the pipe route above ground. Leak noise propagates through up to 250 mm of soil, concrete and block paving. The loudest point in the scan narrows the leak to a 1–2 m section of the run before the correlator is deployed.
Cross-correlator pinpoint
20–40 minTwo sensors clamp to accessible pipe metalwork either side of the garden or driveway run — typically the boundary stop and the internal stop or an external hose tap. Time-of-arrival computation on the SeCorr 08 or Correlux P200 locates the leak within 25–40 cm. Result shown as a graph peak. We mark the floor.
Hydrogen tracer gas confirmation (if needed)
30 minWhere MDPE plastic runs with no metallic reference points, or where the leak is very small, 5% H2 forming gas is introduced under low pressure. A Sewerin RMLD or TG-1 sensor sniffs at the surface above the pipe route. Confirms exact location on any pipe material — including lead and plain-end plastic.
Mark, quote, repair
Same day or next daySingle chalk mark on the driveway or garden surface. Fixed repair quote confirmed on site. Typical access: one block paver lifted, one core drill, or one 300 × 300 mm excavation — not a speculative trench. Patch repairs and mole-and-replace jobs are typically completed the same day.
Repair methods — what happens after detection
Once the leak is pinpointed acoustically, three repair routes are available depending on the pipe material, run length and whether the driveway needs to stay intact. The repair route is agreed with you before any ground is broken.
Patch repair
£380–£580Small excavation at the located leak point only. New compression fitting or push-fit coupling fitted and pressure-tested. Surface reinstatement included — block paver relaid, concrete patched, turf replaced. Best for single isolated leak on MDPE pipe.
Mole-and-replace
£680–£1,200A soil mole borer is driven under the driveway along the pipe route. New MDPE pipe is pulled through behind it. No driveway excavation — block pavers are undisturbed except at entry and exit points. Best for MDPE pipe under block paving where the pipe is old or where multiple leaks may exist.
Full replacement
£1,200–£2,800Full excavation of the supply run, old lead or failed MDPE removed, new blue MDPE laid from boundary stop to internal stop. Per metre rate applies to the pipe run length. Required for pre-1970 lead pipe and for runs where multiple leak points are found.
Supply pipe detection and repair pricing — London 2026
All prices are fixed and confirmed on the call based on the pipe run length, access type and whether the job is booked as a standard survey or a same-day emergency. No VAT add-ons, no parking surcharge.
| Service | Scope | Typical Cost |
|---|---|---|
| Supply pipe detection survey | Acoustic + correlator, boundary to internal stop including driveway. No find no fee. | £280–£420 |
| Emergency supply pipe detection | Same-day Zones 1–3, 60–120 min response. | £380–£480 |
| Supply pipe patch repair | Excavate to exact located leak only. New compression/push-fit fitting. | £380–£580 |
| Mole-and-replace under driveway | Directional bore, new MDPE pulled through, block paving undisturbed. | £680–£1,200 |
| Lead pipe replacement | Full excavation, lead out, new blue MDPE in. Per metre rate applies. | £1,200–£2,800 |
| Insurance trace & access report | ABI-format written report for insurance claim. | +£100 |
Prices include VAT. Insurance trace and access cover usually pays the survey cost. Full pricing page.
Received a Thames Water leak notice?
If Thames Water has already notified you about a leak on your supply pipe, you have 4 weeks from the notification date to carry out the repair under Section 75 of the Water Industry Act 1991. After that deadline, Thames Water can arrange the repair themselves and invoice you at their own rates.
ERL offers same-day detection surveys specifically to keep customers within this window. See our Thames Water leak notice page for the full process.
After the repair is complete, metered customers can apply to Thames Water for a Leak Allowance — a rebate on the water lost during the period of the leak. This must be claimed within 3 months of the repair date. ERL provides the repair documentation needed to submit this claim.
What we cover
- MDPE supply pipe from boundary stop to internal stopThe full private supply run — from the Thames Water stop tap at the edge of your property to the internal stop tap inside your home.
- Lead supply pipe replacement (pre-1970 properties)Old lead communication pipes detected acoustically and replaced with new blue MDPE compliant with current Water Regulations.
- Supply pipe under block paving driveways (mole-and-replace)Soil mole borer driven under the driveway, new MDPE pulled through behind it. Block pavers stay undisturbed except at entry and exit points.
- Supply pipe under concrete driveways (core drill + patch)Core drilled access at the precise leak location. One small patch, not a full driveway break-up.
- Supply pipe under garden and lawn (minimal reinstatement)Small targeted excavation, turf lifted, reseated and reinstated above the repaired pipe.
- Supply pipe under paths and patios (lifted and relaid)Individual slabs or pavers lifted at the pinpointed location, relaid to match after repair.
- Boundary stop tap repair and replacementSeized, leaking or damaged boundary stop taps repaired or replaced — the valve that controls flow from the main to your property.
- Internal stop tap repair where supply pipe connectsDripping or seized internal stop taps replaced as part of the supply pipe repair visit.
Why customers choose ERL for supply pipe leak detection
- No-dig location — acoustic correlator finds the leak before any ground is broken.
- Mole-and-replace — most driveway supply pipe leaks repaired without lifting a single paver.
- No find no fee — if we can't locate the leak on the survey, you pay nothing.
- Thames Water deadline specialists — same-day detection keeps you within the 4-week Section 75 window.
- Insurance-grade trace and access report included — ABI format, processed by insurers without rework.
Related services and useful guides
- Thames Water Leak Detection London — supply pipe surveys for Thames Water-notified properties.
- Thames Water Leak Notice London — what to do when you receive a Section 75 letter.
- No Find No Fee Leak Detection London — how our no find no fee guarantee works.
- Acoustic Leak Detection London — full acoustic correlation service for all pressurised systems.
Frequently asked questions
How do I know if I have a leak under my driveway?
Will you have to dig up my whole driveway?
How accurate is the leak detection?
My pipe is lead — can you detect and replace it?
Can I claim the repair costs from Thames Water?
Does my buildings insurance cover this?
How long does the detection and repair take?
What is the Thames Water 4-week deadline?
Book your supply pipe leak detection survey
Acoustic survey from £280 — no find no fee. Same-day response across London Zones 1–3. Correlator pinpoint to within 25–40 cm. Mole-and-replace repairs for block paving driveways. ABI-format insurance report within 24 hours.
Fully insured £5M PL • No find no fee • 24/7 response • Co. No. 17120057
Service area
Service Area — All London Boroughs
Supply pipe leak detection attended across all 32 London boroughs and the City of London. Same-day response in Zones 1–3; Zones 4–6 typically same day or next morning.
Talk to a supply pipe leak specialist now
No find no fee. Fixed survey price confirmed on the call. Same-day attendance across London.