# Underground Water Leak Detection Nottingham | No-Dig Tracing > Underground water leak detection in Nottingham: acoustic, correlation and tracer gas pinpoint supply-pipe leaks before any digging. Open 7 days, 9am–7pm. URL: https://nottsleakdetection.co.uk/underground-water-leak-detection/ 1. [Home](https://nottsleakdetection.co.uk/) 2. Underground Water Leak Detection # No-Dig Underground Water Leak Detection in Nottingham [Notts Leak Detection](https://nottsleakdetection.co.uk/) provides underground water leak detection on the supply pipe between your boundary and your house, across Nottingham and Nottinghamshire. The leak is found from the surface, marked on the ground and written up before anyone lifts a slab. Book leak detection 0115 839 0791 (+441158390791) [Request a quote](https://nottsleakdetection.co.uk/contact/) Lines open Monday–Sunday, 9am–7pm. ![Engineer sweeping a tracer gas detector over a tarmac drive in Nottingham to find an underground water leak](https://nottsleakdetection.co.uk/images/engineer-sweeping-tracer-gas-detector-over-tarmac-drive-nottingham.webp) - Acoustic ground microphones - Leak noise correlation - Tracer gas: 5% hydrogen, 95% nitrogen - Meter step tests - Pressure testing - Pipe route tracing Last updated: 28 September 2026 A supply pipe can leak for months without a damp patch, because the water drains down into the ground instead of up. On a water meter you pay for every litre of it, and the first sign is usually a bill that has doubled or tripled. Underground water leak detection finds the exact spot on the buried pipe so it can be fixed through one small hole. The supply pipe runs from the boundary stop tap, usually in the pavement or at the edge of the drive, to the stop tap inside your house. [Severn Trent says](https://www.stwater.co.uk/my-supply/tap-water/my-water-pipes/water-pipe-responsibility/) that pipe belongs to the homeowner, even where it crosses someone else’s land. So when the meter shows water going missing on your side, finding it is your job. ## What we do on the first visit The visit starts with the stop taps. With the internal stop tap closed and nothing running, the meter should stand still. If it moves, the loss is on the buried supply pipe. If it only moves with the internal tap open, the leak is inside the house, which is a different job. Next comes the route. The supply pipe rarely runs in a straight line from the meter to the kitchen, so we trace it and find out what it is made of. Older Nottingham homes may still have lead or iron. Newer and replaced supplies are usually blue MDPE plastic. The material decides which method will work best. Then a pressure test on the supply pipe confirms it is losing water, before any time is spent listening for the leak. ## How the leak is pinpointed ### Acoustic ground microphones Water escaping under mains pressure makes a hiss. A ground microphone placed on the surface every metre or so along the route picks up where that noise is loudest. It works well on metal and lead pipes. Plastic pipe carries sound much less well, so a quiet leak on MDPE can be hard to hear. ### Leak noise correlation Two sensors go on fittings at either end of a section, such as the boundary stop tap and the internal stop tap. The correlator measures how long the leak noise takes to reach each sensor and works out where between them it started. This needs access to the pipe at both ends. ### Tracer gas When a leak is too quiet to hear, the pipe is drained and filled with a non-flammable mix of 5% hydrogen and 95% nitrogen. Hydrogen is the lightest gas there is, and it works its way up through soil, tarmac and paving joints. A detector swept over the surface finds where it comes out. This is the method for deep plastic pipes and leaks under hard standing. ### Meter step tests On longer or branched supplies, such as a pipe that also feeds a garden tap or an outbuilding, valves are closed one section at a time while the meter is watched. The section where the flow stops is the one with the leak. ## Paying for it: insurance and Severn Trent Two things can bring some of the money back. Many buildings insurance policies include trace and access cover, which pays to find a leak and to open up and make good the area around it. Most do not pay to replace a worn-out pipe, and limits and excesses vary. Check the policy schedule before you book, and see [what trace and access covers](https://nottsleakdetection.co.uk/guide/trace-and-access-cover/). Separately, once a supply-pipe leak is repaired, [Severn Trent can refund the water you lost](https://www.stwater.co.uk/my-supply/leakage/leakage-allowance/) as a one-off. It covers up to 12 months or two bills, based on actual meter readings. The repair has to be done first, so keep the invoice and the leak report together. [How the Severn Trent leak allowance works](https://nottsleakdetection.co.uk/guide/severn-trent-leak-allowance/) goes through the claim step by step. ## What's included - Meter and stop-tap test to confirm the leak is on your side - Supply pipe route traced from the boundary to the house - Pressure test of the supply pipe - Acoustic ground microphone survey along the route - Leak noise correlation where there are fittings to connect to - Tracer gas if the leak is too quiet to hear - Leak position marked on the ground - Written report with photos, method and next steps ## How the options compare Underground Water Leak Detection: options compared Compare Do it yourself Dig-and-hope operator Proper leak detection How the leak is found Following the wettest patch Digging trial holes Meter test, then acoustic, correlation or tracer gas What gets dug up Whatever looks likely Trenches until it turns up One marked hole for the repair Plastic (MDPE) pipe Very hard to trace Hit and miss Tracer gas finds leaks that make little noise Paperwork afterwards None An invoice Written report for Severn Trent or your insurer If the pipe is shared Unclear whose section Often argued over Leak located on the traced route ## Related resources - [Decision Guide How much does leak detection cost in Nottingham?](https://nottsleakdetection.co.uk/guide/leak-detection-cost/) - [Learn How to find a water leak underground](https://nottsleakdetection.co.uk/guide/how-to-find-water-leak-underground/) - [Learn Can a water leak cause subsidence?](https://nottsleakdetection.co.uk/guide/can-a-water-leak-cause-subsidence/) - [Learn Who is responsible for the water supply pipe?](https://nottsleakdetection.co.uk/guide/who-is-responsible-for-water-supply-pipe/) - [Learn How does the Severn Trent leak allowance work?](https://nottsleakdetection.co.uk/guide/severn-trent-leak-allowance/) Water coming up now? 1. 1Turn off your internal stop tap. It is usually under the kitchen sink. 2. 2Water in the road or on the pavement? That is Severn Trent's: call 0800 783 4444 (+448007834444). 3. 3On your side of the boundary? Call us, 9am–7pm, 7 days. 0115 839 0791 (+441158390791) Standards and rules we work to - Water Supply (Water Fittings) Regulations 1999 - WRAS-approved pipe and fittings on any repair - Severn Trent's published split of pipe responsibility - Non-flammable 5% hydrogen tracer gas Step by step ## What happens, from call to report 1. ### Call and meter test Over the phone you turn off the internal stop tap and watch the meter. If it still moves, the leak is on the buried pipe. 2. ### Trace and test the pipe On site we find the pipe's route and material, then pressure-test it to confirm the loss. 3. ### Pinpoint Acoustic microphones and correlation listen for the leak. Tracer gas takes over where it is too quiet. 4. ### Mark and report The spot is marked on the ground and written up, with the repair or replacement options. The work ## How the work looks Illustrative photos of the methods and finish described on this page. They are not records of particular customers' jobs. - ![Acoustic ground microphone sensor pad on block paving, listening for an underground water leak, Nottingham](https://nottsleakdetection.co.uk/images/ground-microphone-sensor-pad-on-block-paving-nottingham.webp) Acoustic ground microphone sensor pad on block paving, listening for an underground water leak - ![Tracer gas cylinder and regulator connected at a stop tap for underground leak detection, Nottingham](https://nottsleakdetection.co.uk/images/tracer-gas-cylinder-and-regulator-by-stop-tap-cover-nottingham.webp) Tracer gas cylinder and regulator connected at a stop tap for underground leak detection - ![Leak position marked with a painted cross on a drive after underground leak detection, Nottingham](https://nottsleakdetection.co.uk/images/leak-position-marked-with-paint-cross-on-drive-nottingham.webp) Leak position marked with a painted cross on a drive after underground leak detection - ![Pressure test gauge fitted in a boundary box to test a water supply pipe, Nottingham](https://nottsleakdetection.co.uk/images/pressure-test-gauge-on-supply-pipe-in-boundary-box-nottingham.webp) Pressure test gauge fitted in a boundary box to test a water supply pipe ![Wet patch on a block-paved drive over a hidden supply pipe leak, Nottingham](https://nottsleakdetection.co.uk/images/wet-patch-on-block-paved-drive-nottingham.webp) **Before:** Wet patch on a block-paved drive over a hidden supply pipe leak ![The same drive with the blocks relaid after the leak was found and fixed, Nottingham](https://nottsleakdetection.co.uk/images/block-paved-drive-relaid-after-leak-repair-nottingham.webp) **After:** The same drive with the blocks relaid after the leak was found and fixed Meter moving with the stop tap off? Get the leak pinpointed. Book underground leak detection anywhere in Nottingham or Nottinghamshire. Lines open Monday–Sunday, 9am–7pm. 0115 839 0791 (+441158390791) [Request a quote](https://nottsleakdetection.co.uk/contact/) Where we work ## Where we work in Nottingham and Nottinghamshire Based in Nottingham, we work across the whole county. These towns have their own local pages: - [Leak detection in West Bridgford](https://nottsleakdetection.co.uk/service-areas/west-bridgford/) - [Leak detection in Beeston](https://nottsleakdetection.co.uk/service-areas/beeston/) - [Leak detection in Mansfield](https://nottsleakdetection.co.uk/service-areas/mansfield/) - [All service areas](https://nottsleakdetection.co.uk/service-areas/) Questions ## Underground Water Leak Detection: common questions ### How accurate is underground leak detection? The aim is a marked spot small enough for a single repair hole. How close we get depends on the pipe material, its depth and the ground above it. Deep plastic pipe under soil is the hardest to hear, which is when tracer gas is used instead of listening. ### Can you find a leak under a tarmac or block-paved drive? Yes. Leak noise carries through hard surfaces, and hydrogen tracer gas passes up through tarmac, paving joints and soil. Only the section over the leak needs lifting. [Leaks under a driveway](https://nottsleakdetection.co.uk/water-leak-under-driveway/) covers this in more detail. ### What if the leak is on Severn Trent's side? Then it is not yours to pay for. We tell you on the day, and you report it to Severn Trent free on 0800 783 4444 (+448007834444). Severn Trent owns the main, the communication pipe, the boundary stop tap and the meter. ### How long does it take? It depends on the length of the pipe and the method needed. An acoustic survey on a short run is quicker. Tracer gas takes longer, because the pipe has to be drained and filled with gas first. You get a time estimate when you book. ### Do you cover my part of Nottinghamshire? Yes. We cover Nottingham and the rest of Nottinghamshire, including [West Bridgford](https://nottsleakdetection.co.uk/service-areas/west-bridgford/), [Beeston](https://nottsleakdetection.co.uk/service-areas/beeston/), [Mansfield](https://nottsleakdetection.co.uk/service-areas/mansfield/), Arnold, Hucknall and Carlton, plus Ilkeston and Long Eaton over the Derbyshire border. Lines are open Monday–Sunday, 9am–7pm. Call 0115 839 0791 (+441158390791) with your postcode and we will confirm. ### Are you open 24 hours? No. Lines are open Monday to Sunday, 9am to 7pm. Out of hours, turn off your internal stop tap to stop the flow and call us in the morning. If water is coming up in the road or on the pavement, that is on Severn Trent's side: report it free on 0800 783 4444 (+448007834444). Related ## Related services - ### [Water Supply Pipe Repair](https://nottsleakdetection.co.uk/water-supply-pipe-repair/) One leak on your supply pipe, found and fixed through a single small hole. View service - ### [Trace and Access](https://nottsleakdetection.co.uk/trace-and-access/) Find the leak, open up only what is needed and document it for your insurer's trace and access claim. View service - ### [Water Meter Leak](https://nottsleakdetection.co.uk/water-meter-leak/) Meter still turning with everything off? Work out whether the water is going on your side or Severn Trent's. View service Find the underground leak before anyone digs. Call to book, or send a quote request and we will ring you back. Lines open Monday–Sunday, 9am–7pm. 0115 839 0791 (+441158390791) [Request a quote](https://nottsleakdetection.co.uk/contact/)