Plumbing & Heating and Water Mains Specialist · Based in Hemel Hempstead, Hertfordshire
Darren Smith is a leak detection engineer specialising in identifying hidden water leaks using thermal imaging, acoustic listening equipment, and tracer gas.
Darren is part of ADI Leak Detection — the UK's leading leak detection specialist with 1,250+ five-star Trustpilot reviews, full CIPHE and WIAPS accreditation, and £5 million public liability insurance.
Why Trust Darren to Find Your Leak?
Darren brings 40 years in plumbing and heating alongside 6 years of specialist leak detection experience. He holds an NVQ Level 2 in Plumbing and Heating, a Water Regulations Certificate, and a Utility SHEA (Water) qualification. He is particularly known for his work on plumbing and heating systems and water mains.
Engineer Facts
Plumbing & Heating Experience40 years
Leak Detection Experience6 years
QualifiedNVQ Level 2 Plumbing and Heating
QualifiedEnergy Efficiency Part L
QualifiedWater Regulations Certificate
QualifiedUnvented Hot Water Systems
QualifiedUtility SHEA (Water)
Leak Detection Jobs Completed For ADI Since 20211,037
Leak Detection Case Studies by Darren Smith
Recent leak investigations carried out by Darren Smith across central heating, water mains, underfloor heating and bathroom leak detection.
Internal Cold Mains LeakHemel Hempstead
Internal Cold Mains Leak / Hemel Hempstead
A property in HP11 presented with damp appearing on the hallway floor and left-hand side wall. Internal mains leak located in hallway, excavated and repaired.
Found
Underground Mains LeakEnfield Town
Underground Mains Leak / Enfield Town
At a property in N14, the water meter was registering a continuous flow of approximately 0.5 litres per hour with all known outlets closed. Underground mains leak found in back garden, excavated and repaired.
Found
Central Heating LeakEast Dereham
Central Heating Leak / East Dereham
At a property in IP25, the central heating system had been losing pressure over approximately 12 hours. Leak found in hallway floor, failed copper bend replaced.
Found
Hot Water System LeakBurnham
Hot Water System Leak / Burnham
A property in SL1 was experiencing persistent damp throughout the hallway, with wet floors in both the hallway and the downstairs WC. Hot supply leak found at kitchen doorway, pipe replaced.
Found
Internal Cold Mains LeakCoventry
Internal Cold Mains Leak / Coventry
At a property in CV5, water was pooling in the cupboard beneath the staircase, and both the hallway and bathroom floors were uniformly damp. Hot supply pipe leak located in hallway and repaired.
Found
Underground Mains LeakDunstable
Underground Mains Leak / Dunstable
A property in LU6 — a working petrol garage — was losing water continuously, with the meter registering 15 litres per minute of usage while every known outlet was closed. Multiple mains leaks found in access chamber, pipework replaced.
Found
Internal Cold Mains LeakWokingham
Internal Cold Mains Leak / Wokingham
A property in RG40 was showing clear signs of a water leak, with damp found throughout the kitchen floor and water damage to the lower 300mm of the walls. Leak found at kitchen wall, pipe renewed and pressure tested.
Found
Central Heating LeakBurnham
Central Heating Leak / Burnham
At a property in SL6, the heating system had developed a hidden leak that was causing pressure loss across the circuit. Leak found on soldered tee beneath shower room floor, repaired.
Found
Underground Mains LeakColnbrook
Underground Mains Leak / Colnbrook
A property in SL3 had a water meter showing continuous usage, indicating water was being lost somewhere in the supply system even when no taps or appliances were in use. Open-ended old mains and obsolete stopvalve found and capped.
Found
Reviews of Darren's Work
Verified Trustpilot reviews
Real Trustpilot feedback from customers Darren has attended.
★★★★★
Up and Running Again
Had a serious leak on my central heating pipework buried somewhere in my concrete floor downstairs preventing me from running my central heating. No visible signs of where the leak was so called ADI. Darren arrived on time on the allotted day and immediately got to work after a brief explanation from me of what I knew. Within a relatively short period of time, couple of hours, he pinned down where the leak was using his gas detection equipment. Went to work digging up the area of where the leak was and soon was able to show me where the hole was in the pipe. Replaced the corroded pipe with a new length, performed a pressure test of the system and then reinstated the central heating system to ensure as far as possible all was well. Extremely impressed with the professionalism shown by Darren and would not hesitate to use again. Thank you.
★★★★★
Great service - above and beyond
Great service from Darren at ADI for really going the extra mile to track down a difficult and persistent central heating leak. He arrived promptly at 9:30am and didn't leave until 8:45pm on Bank Holiday Friday when the leak was finally tracked down and fixed. I was really impressed with Darren's skill and patience and he worked tirelessly all day accepting only 3 cups of coffee (despite lots of offers). Also kudos to Dave in the office for his customer service - I would definitely recommend ADI.
★★★★★
Exceptional service provided by ADI
All of the interaction we had with ADI, from the initial phone booking process with Christian to the engineer visit from Darren was excellent. Darren was prompt to visit the property and assess the situation making sure all avenues of investigation and leak detection were carried out calmly and professionally. He kept us informed of his progress at all stages of the investigation and subsequent fix that was put into place. And he properly cleaned up after himself too which was much appreciated. Thoroughly recommend ADI and would not hesitate to use their services again
★★★★★
Invisable leak professionally and efficiently resolved.
We had an invisable leak . ADI leak detection gave us an appointment within a week which suited us as there was no ongoing damage . Darren attended. . He was professional and knew what he was doing . He found the leak within 1 hour and proceeded to locate the precise location , which was in our garden, undertook the repair and replaced everything as it was . The cost was significant but the company were upfront about this and gave a detailed quotation and in line with other providers . They did charge £60 for " extras" supply of the hydroogen gas tracer etc but again this was in line with their estimates. In total the job took 6 hours from start to finish .
★★★★★
What an absolute pleasure to be proved…
What an absolute pleasure to be proved wrong. Notwithstanding having ADI recommended by a very reliable source, I was doubtful that they could really do what they promised, i.e. Find the leak in our Central Heating pipework hidden in one of two places: (i) A ceramic tiled floor on floorboards, ply-wood and joists, with electric under-floor heating, or (ii) A carpeted area, again with floorboards, ply-wood and joists, all almost hermitically sealed… Darren turned up exactly on-time and undaunted by the task, set out narrowing down the general area with the use of tracer-gas – a task that was very far from easy, due to the way the floors were in both areas “sealed”. He then narrowed it down further with acoustic testing and located the leak, albeit after 3 hours of dedicated work. The leak was very fine mist, so almost impossible to detect using normal equipment, but he did it and found the cause; a badly soldered joint from sixty year ago, which had failed when our new non-vented system was installed a month ago…. Darren made the repair, refitted the floor and carpet, and left us as though nothing had been touched. So a seriously brilliant result and without doubt worth every single penny.
★★★★★
I had a massive leak through the living…
I had a massive leak through the living room ceiling on the 28th Nov. I called my insurance Admiral thinking I would be able to get someone out under Trace and Access but they refused to send anyone out even as an emergency to secure the premises, After hrs searching for plumbers with leak detection equipment found ADI leak Detection, from the minute i spoke to Joe i knew i was in safe hands, the engineer Darren was absolutely fantastic in locating where the leak was coming from and fixing the issue stopping the issue causing any further damage. The only downside to this firm is there prices are quite high in comparison to some others out there ended up paying £975 for Trace and Access and £300 for the repair but it was a Saturday and needed someone ASAP!
★★★★★
Fastastic work
Darren was excellent at finding the leak in my property. Communication about the planning and work was great He explained all the steps and was very efficient and cleaned up afterwards. I would have no hesitation in using this company again.
★★★★★
ADI sent us two excellent water leak detectorists.
ADI sent us two excellent water leak detectorists - Danny and Darren - who spent the day at our rather large property trying to find the water leak. When found they did a superb job, fixed the leaking pipe, filled in the hole and tidied up. They explained what they were doing throughout in a knowledgeable and professional way. To be recommended.
★★★★★
Did exactly as promised
Did exactly as promised. I would highly recommend using them. Darren detected the leak precisely and opened up the concrete floor with minimal intrusion. He also fixed the issue and cleaned up around it .
★★★★★
Great service and expertise
Darren from ADI was so professional and polite. We thought we would have to access the leak via the bathroom floor, but Darren found another solution that avoided removing the shower tray and digging up the floor. Great result. Thank you Darren. Would definitely recommend ADI to find the leak and fix it, especially Darren.
Darren spent 40 years working in plumbing and heating before moving into leak detection, which means he understands how buildings are plumbed — not just how to test them. That background is especially useful on complex central heating and water mains jobs, where knowing what lies behind the wall or under the floor shapes how an investigation is run. On a job, he uses non-invasive equipment first, only recommending any form of access when the evidence points clearly to a specific location. He also has strong opinions about pineapple on pizza — it belongs there.
Darren leads with non-invasive methods, using acoustic listening equipment to detect the sound of a pressurised leak through walls, floors, and ground. Thermal imaging identifies temperature anomalies caused by escaping water without requiring any surface to be opened up. Where a direct visual inspection is needed, a borescope camera is inserted into a void or pipe, and tracer gas is used on pressurised systems to pinpoint a leak's exact location.
What experience and qualifications does Darren have?
Darren has 40 years in plumbing and heating and 6 years in leak detection. His qualifications include an NVQ Level 2 in Plumbing and Heating, Energy Efficiency Part L, a Water Regulations Certificate, Unvented Hot Water Systems, and a Utility SHEA (Water) qualification.
What types of properties does Darren work on?
Darren works on both residential and commercial properties, covering a wide range of leak types including those in central heating systems, underfloor heating, bathroom plumbing, drains, and buried water mains. His background in plumbing and heating means he is well placed on older or more complex systems where understanding the original installation helps guide the investigation.
When should you call Darren for leak detection?
If your water meter is turning with no taps open, you have unexplained damp patches, a rising water bill, or a central heating system that keeps losing pressure, those are all signs worth investigating before the damage gets worse. Call ADI Leak Detection on 0800 731 3843 to book an investigation — ADI will aim to assign Darren where he is available in your area.
How Darren finds your leak
Darren follows a consistent five-stage process on every visit. The approach is non-invasive and designed to isolate the fault before any disruption to your property.
Initial assessment. Review symptoms with the customer, check visible evidence, and identify the most likely system involved.
Selection of the right detection method. Pick the combination of thermal imaging, tracer gas, acoustic listening, or moisture mapping most likely to isolate the fault.
Non-invasive testing. Run the chosen method across the candidate area — no excavation or destructive investigation until the leak is confirmed.
Leak confirmation. Cross-verify the finding with a second method where possible, mark the exact location, and document the evidence.
Reporting and next steps. Provide a written report, photographs, and recommended repair options.
What Darren Smith Does
Services and systems
Darren works across central heating, underfloor heating, water mains, bathroom plumbing, drains, and underground pipework. His specialisms cover the full range from internal bathroom leak detection and drain investigations through to buried underground supply pipes and mains connections.
Coverage
Darren covers a broad area of England, working across London and the South East, the South, the East of England, the East Midlands, and parts of the South West — including counties such as Bedfordshire, Buckinghamshire, Hertfordshire, Kent, Surrey, Essex, and Warwickshire.
Property types and complexity
Darren works on residential and commercial properties, handling everything from straightforward internal leaks in bathrooms and heating systems through to more involved investigations on buried mains pipes and underground supply lines. His 40-year plumbing and heating background makes him particularly well-suited to older or more complex heating installations where system knowledge is as important as detection equipment.
Areas Covered
Darren carries out leak detection surveys across Greater London, South East, East Anglia, South West & The Midlands. His work includes domestic and commercial investigations involving central heating, water mains, underfloor heating, bathroom, and drain leaks.
