Specialist Engineers
Focused investigation for water supply pipe leaks and external water leaks.
Mains Water Leak Detection
Mains Water Leak Detection
Locate hidden underground water leaks, water supply pipe failures and mains water leaks using thermal imaging, tracer gas and non-destructive investigation methods.
We investigate high water bills with no visible leak, water meters constantly running, external supply pipe leaks and hidden water loss between the meter and property.
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- Water Meter Running
- Underground Leaks
Non-Destructive Methods
Tracer gas, acoustic detection and thermal imaging used before excavation.
Coverage Across Southern England
London, Surrey, Berkshire, Buckinghamshire, Oxfordshire, Hampshire and Sussex.
Insurance Support
Written findings and photographs can be provided for claim support.
What It Means
What Is A Mains Water Leak?
A mains water leak is water loss from the supply pipe serving a property. This can include the pipework between the meter and the building, external pipe runs, underground pipework and hidden connections.
Supply pipe responsibility can vary depending on the location of the leak, meter position and property boundary. The first priority is identifying where water is escaping and whether the issue is internal or external before excavation or access work begins.
Because these leaks are often underground, water loss can remain unnoticed until bills rise, the meter keeps running or damp ground appears outside. If the issue appears to be inside the property, our broader water leak detection service may be more appropriate.
Supply Pipe Routes
Understanding Where Mains Water Leaks Happen
Mains water leaks are not always visible at the surface. A structured investigation helps separate supply pipe leaks from internal plumbing, heating system leaks and drainage-related water damage.
Private supply pipe
The private supply pipe connects the property to the water network. Responsibility often depends on the meter, boundary and supply arrangement, so the exact position should be confirmed before repair is arranged.
Public water-company main
The public main forms part of the wider water-company network. Suspected leaks on that network should be discussed with the supplier, which can confirm its responsibility boundary.
Shared or managed supplies
Flats, older properties, portfolios and managed sites can share supply routes. Landlords, managing agents and the water supplier may need to confirm how the pipework is arranged.
A running meter can still be caused by internal pipework, so the investigation considers both the external supply route and the property before responsibility is assigned. For business premises, managed blocks or property portfolios, our commercial leak detection service provides the appropriate property and stakeholder context.
Symptoms
Common Signs Of A Mains Water Leak
Water bill suddenly increased
A high water bill leak can indicate hidden water loss from supply pipework between the meter and property.
Learn moreWater meter constantly running
A meter that continues moving when taps are off often points to an active mains water leak.
Learn moreDamp areas outdoors
Unexpected wet patches on drives, paths, lawns or external walls can indicate an underground water leak.
Learn moreReduced water pressure
Lower water pressure may be linked to a supply pipe failure or leak on the incoming mains route.
Learn moreUnexplained water loss
Ongoing water usage without visible internal leaks may require mains water leak investigation.
Learn moreSoft or wet ground
Soft ground, pooling water or saturated soil can indicate a hidden water supply leak below the surface.
Learn moreIf the meter is accessible, our water meter leak-test guide explains a safe preliminary check. Meter movement can indicate water loss, but it does not identify whether the source is internal, on a private supply pipe or on the water-company side.
Process
How We Locate Underground Water Leaks
01
Initial Assessment
We review water bills, meter behaviour, property layout and the likely supply pipe route.
02
Leak Investigation
Tracer gas, acoustic detection and other non-destructive methods are used where appropriate.
03
Leak Location Confirmed
Findings are correlated to identify the likely underground water leak location.
04
Report & Recommendations
You receive clear findings to support excavation planning, repair or insurance requirements.
Why It Matters
Why Specialist Detection Matters
Avoid unnecessary excavation
Leak detection narrows the likely leak position before contractors open drives, paths, lawns or floors.
Locate leak before digging
A targeted investigation helps repair teams plan access around evidence rather than guesswork.
Tracer gas investigations
Where pipework can be isolated safely, tracer gas can help locate hidden supply pipe leaks below ground.
Acoustic detection methods
Acoustic listening can support investigations on pressurised mains and external pipe routes.
Evidence-led findings
Findings can support repair planning, landlord decisions, insurer discussions and water company conversations.
Reduced disruption
Confirming the likely leak area helps reduce unnecessary damage to hardstanding, landscaping or internal finishes.
Technology
Technology Used For Mains Water Leak Detection
Mains water leak detection commonly combines tracer gas leak detection, acoustic detection and route assessment. Where moisture has entered the building, moisture mapping can help document affected areas.
Supporting Methods
Additional Investigation Techniques
Endoscopic Camera Inspection
Small inspection cameras are used to visually check concealed voids, pipe routes and difficult-to-access areas before opening up.
Dye Testing
Coloured test dye can help confirm water paths, waste leaks, bathroom leaks and suspected escape routes.
Pressure Testing
Controlled pressure testing helps identify whether sealed pipework or heating circuits are losing pressure.
Reporting
What A Mains Water Leak Report Can Include
A written report can help homeowners, landlords, managing agents, contractors and insurers understand the evidence before repair work is planned.
- Likely leak location or affected supply route
- Investigation methods used
- Photographic evidence where available
- Meter behaviour and symptom notes
- Recommended next steps for access or repair
- Supporting information for insurers, landlords or contractors
What Happens After The Leak Is Located?
We explain the likely leak position, the evidence gathered and the access route recommended by the investigation.
The next repair route depends on whether the affected pipework is private, shared or within the water supplier's responsibility. The property owner, managing agent or supplier can then arrange the appropriate access and repair.
Permanent repair and reinstatement are separate from leak location unless they are included in the agreed scope of work.
If the investigation forms part of a claim, see our insurance leak investigation and trace and access services.
Recent Work
Recent Mains Water Leak Investigations
Real project examples help show the types of high usage, running meter and supply pipe issues we investigate.
Kingston, London
Mains Water LeakMains Water Leak Detection in Kingston
Rushing water heard when no services were in use was traced to a hole in a lead supply pipe and repaired in one visit.
View case study
Ascot, Berkshire
Mains Water LeakMains Water Leak Detection in Ascot
An Ascot mains water leak investigation used moisture, thermal and tracer gas methods to trace concealed pipework beneath flooring.
View case study
South Woodford, London
Mains Water LeakMains Water Leak Detection in South Woodford
High water consumption traced to rodent-damaged plastic supply pipework and repaired in one day.
View case studyRelated Services
Related Leak Detection Services
01
Water Leak Detection
Structured investigation for hidden leaks in pipework, floors, walls and ceilings.
02
Trace & Access
Leak tracing and access evidence for concealed pipework and insurance claim requirements.
03
Insurance Leak Investigation
Evidence-led leak reports prepared for insurer, loss assessor and claim requirements.
04
Central Heating Leak Detection
Heating system leak detection for boiler pressure loss and hidden heating pipe leaks.
09
Damp Investigation
Damp surveys and moisture mapping for water ingress and hidden leak symptoms.
10
Waste Pipe Leak Detection
Investigation for hidden waste pipe, soil pipe and foul water leak symptoms.
Coverage
Areas We Cover
Mains water leak detection surveys are available across London, Surrey, Berkshire, Buckinghamshire, Oxfordshire, Hampshire and Sussex for homeowners, landlords, businesses and managing agents.
FAQs
Mains Water Leak Detection FAQs
Can a mains water leak increase my water bill?
Yes. A mains water leak or hidden water supply pipe leak can cause a sudden increase in water usage, especially if the leak is between the meter and property.
How do you find underground water leaks?
We use non-destructive leak detection methods such as tracer gas, acoustic detection and route assessment to narrow the likely underground water leak location before excavation.
Will my water meter run continuously if I have a leak?
A water meter that keeps running when all outlets are off can indicate an active leak on the supply pipe or internal pipework. It should be investigated promptly.
Do you need to excavate immediately?
No. The investigation starts with non-destructive methods to locate the likely leak position before excavation or access work is recommended.
Can findings support an insurance claim?
Yes. Written findings and photographs can support insurance, trace and access or repair planning requirements. Your insurer decides what is covered.
Get Expert Help
Request Mains Water Leak Detection
Speak to a specialist about a high water bill leak, running meter, underground water leak or suspected external supply pipe failure.
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