# What an underground leak detection visit looks like > A step-by-step walkthrough of a typical underground leak detection visit: the phone call, the meter test, tracing the pipe, pinpointing the leak and the report. URL: https://nottsleakdetection.co.uk/blog/underground-leak-detection-visit-walkthrough/ 1. [Home](https://nottsleakdetection.co.uk/) 2. [Blog](https://nottsleakdetection.co.uk/blog/) 3. What an underground leak detection visit looks like, start to finish How a job runs # What an underground leak detection visit looks like, start to finish [Notts Leak Detection](https://nottsleakdetection.co.uk/) walks through how a typical underground leak detection visit runs, so you know what to expect and what to have ready. Published 28 September 2026 · By Notts Leak Detection **Illustrative walkthrough.** This describes how a typical job runs. It is not a record of a particular customer's job. Most people have never had a leak located before, so it helps to know how the day runs. This walkthrough follows a typical job on a Nottingham semi with a metered supply and a bill that has doubled. The house and the details are illustrative. ## Before the visit: the phone call The first conversation is about the meter. With every tap off and the internal stop tap closed, does the meter still move? If it does, the water is escaping on the buried supply pipe between the boundary and the house, and a visit makes sense. If it only moves with the internal stop tap open, the leak is inside, often a toilet, and a different kind of visit is needed. Useful things to have ready: - where the internal stop tap is, and whether it turns; - where the meter or boundary box is; - a recent bill and a meter reading; - any letter from the water company about a leak. ## On arrival: confirming it The meter test is repeated on site, because it is the baseline for everything else. The internal stop tap is checked, and the boundary box is opened to look at the meter and the pipe entering the property. ## Tracing the pipe A supply pipe rarely runs in a straight line from the pavement to the kitchen. It may cut across a front garden, run under a drive, or come in at the side of the house. The route is traced and marked, and the pipe material is identified: lead, iron or blue MDPE plastic. The material decides the method. A pressure test on the supply pipe then confirms the loss and shows how fast it is dropping. Recognise your situation? The meter test on the phone is the first step. 0115 839 0791 (+441158390791) ## Pinpointing the leak On a lead or metal pipe, a ground microphone is placed along the marked route and the engineer listens for where the hiss is loudest. Where there are fittings at each end, a leak noise correlator times the sound to calculate the position. On plastic pipe, or under a thick drive, the leak may be too quiet to hear. Then the pipe is drained and filled with a non-flammable 5% hydrogen tracer gas. Hydrogen rises through soil, tarmac and paving joints, and a detector swept over the surface finds where it comes out. The leak position is marked on the ground with paint. ## The report Before leaving, you get the findings: where the leak is, how it was found, what the pipe is made of, and the options. That might be a single repair through one hole, a replacement, or moling a new pipe under the drive. If the pipe is lead, the report flags the water company’s lead replacement scheme. Keep the report. With the repair invoice, it supports a claim for the one-off leakage allowance on the water you lost. ## After the visit The repair is booked, the hole goes in over the marked spot, the leak is fixed, and the pipe is pressure-tested before the ground goes back. A week or two later, a meter reading shows usage back to normal. That reading goes with the allowance claim. For the full service, see [underground water leak detection](https://nottsleakdetection.co.uk/underground-water-leak-detection/). ## Related guides - [Learn How to find a water leak underground](https://nottsleakdetection.co.uk/guide/how-to-find-water-leak-underground/) - [Decision Guide How much does leak detection cost in Nottingham?](https://nottsleakdetection.co.uk/guide/leak-detection-cost/) - [Learn How does the Severn Trent leak allowance work?](https://nottsleakdetection.co.uk/guide/severn-trent-leak-allowance/) - [Learn Who is responsible for the water supply pipe?](https://nottsleakdetection.co.uk/guide/who-is-responsible-for-water-supply-pipe/) Think you have a leak? Get it located and written up. Lines open Monday–Sunday, 9am–7pm. 0115 839 0791 (+441158390791) [Request a quote](https://nottsleakdetection.co.uk/contact/)