McFadden Utilities is a water leak detection specialist based in Hertfordshire, delivering network-scale leak detection, commercial site surveys, and subcontract leak detection for Tier 1 civils contractors across London and the South East. Typical work includes mains leak detection on adopted water networks, preventive leak detection surveys for water companies, commercial site water loss surveys, Tier 2 subcontract leak detection on civils frameworks, and supply pipe leak detection for property owners.
Water leak detection is the work of locating a leak in a water supply system accurately enough to access and repair it. Most leaks don’t announce themselves visibly. A trunk main leak can run for weeks underground before surface water appears. A commercial site leak can hide inside a building envelope until the water bill flags the water loss. A supply pipe leak can track through garden or verge without showing on the surface at all. The job of leak detection is to take a suspected leak and pin it down to the specific location where access can be made.
McFadden’s leak detection scope covers the full scale range from mains trunk leak detection through to property-level supply pipe surveys. Mains leak detection uses acoustic techniques, correlator equipment, and pressure monitoring to locate leaks on large adopted water mains, typically under framework contracts with water companies or as Tier 2 work for civils contractors. Commercial site surveys combine acoustic equipment, thermal imaging where appropriate, and structural moisture mapping to locate leaks inside building envelopes or across large sites. Supply pipe surveys use the same techniques at smaller scale for supply pipe leaks affecting individual properties.
Finding the leak is the part that needs skill. Once you know where it is, the repair is straightforward. Most of what separates a good leak detection job from a bad one happens before the first shovel goes in the ground.
Paul McFadden, Director
When working under water company framework contracts, the water company typically carries out its own leakage detection. Once a leak is located, McFadden is dispatched to undertake the repair work, with 24/7 standby crews available for reactive callout. Accurate detection before arrival on site saves significant time and disruption compared to trial-hole digging across a suspected area. For Tier 2 subcontract work on civils framework contracts, leak repair often pairs with flow meter installation and pressure-reducing valve work, giving the main contractor a single accredited subcontractor for multiple scope items.
Commercial site leak detection covers industrial sites, commercial properties, retail and multi-occupier buildings, and any site where an unexplained water loss needs locating. The technique library covers acoustic correlators for buried pipework, ground microphones for verifying the location after correlation, thermal imaging where heat loss gives a leak away, pressure testing for isolating the affected pipe run, and tracer gas where none of the other methods are producing a result. Where the leak sits within McFadden’s capability, the team can move directly from detection to excavation, repair, and reinstatement on the same job.
Supply pipe leak detection for property owners is delivered on the same basis at smaller scale. Common scenarios include unexplained water bill increases, damp patches in gardens or verges without an obvious source, and supply pressure problems. The teams locate the leak, confirm the position, and can proceed with excavation and repair or produce a report for insurance purposes where that’s the route being taken. For complex leaks inside the building (under floors, behind walls etc.), McFadden coordinates with specialist domestic leak detection partners rather than stretching utility expertise into pure plumbing work.
A leak detection job runs in four phases, whether the scope is a water company framework survey or an individual supply pipe investigation. The techniques scale with the job. The method stays the same.
Site visit, review of the scope (suspected mains leak, commercial loss, or supply pipe issue), assessment of access points, network diagrams or site plans if available, and confirmation of which detection method fits the scenario.
Acoustic survey with correlator equipment on the suspected section, cross-reference with pressure monitoring where network data is available, thermal imaging or ground microphone work where the initial correlation needs confirming.
Ground microphone walk-over to pinpoint the leak position within a metre accuracy, confirmation via secondary technique (tracer gas or pressure isolation) where the first technique leaves doubt, marking the precise location on site for the excavation team.
Either handover of the confirmed leak location with supporting documentation for the client's own repair team, or McFadden's own teams proceeding directly to excavation, repair, and reinstatement under the same framework.
Leak detection teams work from the Hertfordshire depot, covering London and the wider South East as standard. Framework contract work takes teams further afield as schemes require. 24/7 emergency response is available for existing contract clients.
The questions we hear most about water leak detection.
McFadden delivers water leak detection across the full scale range. Mains leak detection for adopted water networks, typically under water company framework contract or Tier 2 civils subcontract. Commercial site leak detection for industrial, retail, and multi-occupier sites where water loss needs investigating. Supply pipe leak detection for property owners with suspected underground supply pipe leaks. The techniques include acoustic correlation, ground microphone verification, thermal imaging, pressure testing, and tracer gas detection, selected by fit to the scenario.
The technique library covers five methods. Acoustic correlation locates leaks on buried pipework by comparing sound signatures at two sensor points. Ground microphones verify and pinpoint the location once correlation has narrowed the area down. Thermal imaging identifies leaks by temperature differences at the surface or on building envelopes. Pressure testing isolates affected sections of a network or building system to narrow down where the loss is happening. Tracer gas is used when none of the other methods are giving a clear result, injecting a hydrogen-nitrogen mix into the pipe and detecting the escape at the surface. Most jobs use two or three methods in sequence, not one.
Yes. Water company framework leak repair is part of McFadden’s core scope, with 24/7 standby crews available for reactive callout once leaks have been located by the water company’s own detection teams. Tier 2 civils subcontract work is also actively delivered, typically on water utility schemes commissioned through Tier 1 civils contractors holding framework contracts with water companies. The WIRS accreditation and the broader accreditation stack apply in both cases.
Yes. Commercial leak detection covers industrial sites, commercial buildings, retail and multi-occupier buildings, and any site where an unexplained water loss is showing up on the water bill or a meter reading. Detection combines site inspection, network diagram review where available, acoustic and thermal surveys, and targeted pressure testing. Where the leak turns out to sit within the utility scope of capability, McFadden can also proceed directly to excavation and repair on the same job.
Yes, supply pipe leak detection is delivered for property owners. Common scenarios include unexplained water bill increases, damp patches in gardens or verges without an obvious source, and supply pressure problems. The teams locate the leak using the same acoustic and correlation techniques used on larger scale work, confirm the position, and either proceed with excavation and repair or produce a report for insurance purposes where that’s the route the property owner is taking. For complex leaks inside the building (under floors, behind walls, within central heating systems), McFadden coordinates with specialist domestic leak detection partners rather than stretching utility expertise into pure plumbing work.
With acoustic correlation backed up by ground microphone verification, leaks on buried pipework are typically located to within about one metre. That accuracy is what makes targeted excavation possible rather than trial-hole digging across a suspected area. On commercial or internal systems, accuracy depends on access and the method used, but the principle is the same: narrow the location down until excavation or access work has a specific target, not a range.
The core credential for any contractor working on adopted water networks is WIRS accreditation (Water Industry Registration Scheme, Lloyd’s Register), which McFadden holds. WIAPS registration (Water Industry Approved Plumbers Scheme) covers the connection and fitting side. ISO 9001, ISO 14001, and ISO 45001 cover quality management, environmental management, and occupational health and safety respectively. Constructionline Gold and Achilles cover supply chain credentials. SSIP SMAS Worksafe covers the safety scheme in procurement.
McFadden delivers leak detection across Hertfordshire, London, Surrey, Essex, Cambridgeshire, and Berkshire as standard, working from the Hertfordshire depot. Framework contract work takes teams further afield where schemes require. 24/7 emergency response is available for existing contract clients.
Whether it's a water company framework survey, a commercial site with an unexplained water loss, a Tier 2 subcontract enquiry from a civils contractor, or a supply pipe issue on a private property, the leak detection team are happy to talk through the scope and get a quote over. Confidential framework enquiries welcome.
Phone: 01707 648 420
Email: info@tonymcfadden.co.uk