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02080530369

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ENGINEERS AVAILABLE NOW

Pressure Testing for
Leak Detection in London

Your boiler keeps losing pressure. There is no wet patch anywhere. You have checked the obvious places and found nothing. Before a floor is lifted or a wall is opened, the right question is this: is there actually a leak in this section of pipework?

At 0800 Homefix, we answer that question in under an hour. We isolate the affected circuit, apply a controlled test pressure, and monitor whether it holds. A pressure drop confirms a leak is present and tells us exactly where to look next.

Gas Safe Registered
1-Hour Emergency Response
No Call-Out Fee
12-Month Guarantee
Fully Insured
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No call-out fee · Fixed pricing before we start · 7 days a week including bank holidays

Get a Free Quote

Pass/Fail

CLEAR DIAGNOSTIC RESULT.

£0

Call Out Charge

95%

First Time Fix Percentage

±0.1 bar

PRESSURE DROP DETECTED

Gas Safe Registered

Every engineer verified

APHC Members

Trade body accredited

Public Liability Insurance

Your property protected

WaterSafe Approved

Qualified for mains water

NVQ Level 2 & 3

Formally qualified engineers

London’s Trusted Plumbers

Why London Trusts 0800 Homefix
for Pressure Testing

The most common reason a pressure test gets carried out wrong is that the engineer skips the section isolation step. They pressurise the whole system, watch the gauge, and when it drops they confirm a leak exists somewhere. But they still do not know where. That is not a complete diagnostic. It is the first fifteen minutes of one.

We work differently. By isolating sections methodically and testing individual circuits and pipe runs separately, we narrow the location of the fault before any further investigation begins. So when we move to acoustic listening, tracer gas or thermal imaging, we are working on a defined area rather than the whole system. The investigation is faster, and any access work, if it is needed at all, is targeted to within a small area rather than left to guesswork.

That methodical approach is why customers trust us, and it is matched by how we document the work. Section pressure testing comes as standard rather than whole-system testing alone, results are recorded and included in any follow-on insurance report, and we combine pressure testing with other detection methods on the same visit wherever it saves you a second appointment.

  • We carry out section pressure testing as standard, not whole-system testing alone
  • Test results are documented and included in any follow-on insurance report
  • We combine pressure testing with other detection methods on the same visit where needed
  • 1hr emergency response
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What to expect

We Have Been Diagnosing London Plumbing Problems for years

For the full range of leak detection methods we use alongside pressure testing, see our Water Leak Detection and Repair service page.

  • 1hr Emergency Response
  • Gas Safe registered engineers
  • No call-out fee
  • Fixed quote before any work starts
  • 12-month labour guarantee on every repair
  • 7 Days a Week, 365 Days a Year including bank holidays
  • 9.17/10 based on 4301 reviews
Precision Detection

What Sets Our Pressure
Testing Service Apart

Pressure testing is a straightforward diagnostic method when it is carried out correctly. Here is what makes a practical difference on a real job.

01

Section Isolation as Standard

We do not just pressurise the whole system and watch the gauge. We isolate individual circuits and pipe runs to establish which section of the system is losing pressure. This tells us where the leak is, not just that one exists.

02

Accurate Test Conditions

A pressure test is only valid if it is carried out at the correct test pressure for the system type, held for the correct duration, and with appropriate allowance for temperature stabilisation. We follow the correct procedure on every test.

03

Combined with Follow-On Detection

A pressure drop tells you a leak exists and roughly where. It does not give you a precise location. We use acoustic listening, tracer gas or thermal imaging directly after a pressure test to confirm the exact point of failure before any access work is recommended.

04

Documented Test Results

Every pressure test we carry out is documented with the start pressure, the end pressure, the test duration and the result. This documentation is included in any follow-on insurance or trace and access report at no extra cost.

05

Gas Safe on Every Gas Job

Pressure testing on gas pipework requires Gas Safe registration. Every engineer who carries out any gas-related pressure testing holds a current Gas Safe registration. Ask to see the ID card and verify it at GasSafeRegister.co.uk before work begins.

06

12-Month Guarantee on All Repairs

Once the pressure test has confirmed the fault location and the repair has been carried out, every repair is guaranteed for 12 months. If the same fault returns, we come back and address it at no additional cost.

The people behind the service

Meet a Few Of Our Plumbing & Heating Engineers

When you call 0800 Homefix, a real named engineer attends your property. Every person on our London team is Gas Safe registered, NVQ qualified, DBS checked, and carries full ID. Here are some of the engineers who may attend your job.

Neill Young

Leak Detection Specialist

8+ years experience · North, East & West London

APHC Member
WaterSafe Approved

With over 8 years of experience servicing North, East and West London, I specialise in locating hidden leaks quickly and accurately using non-invasive detection methods. As a fully Gas Safe Registered engineer with NVQ Level 3 qualifications, I focus on delivering reliable, professional solutions that minimise disruption and help customers avoid unnecessary damage and repair costs.

“I regularly find hidden leaks without removing tiles or floors—most customers are surprised how quickly we can locate the issue without damage.”

James Emmerson

Plumbing & Heating Engineer

13+ years experience – London
Gas Safe Registered
NVQ Level 3 Plumbing & Heating
G3 Certified

I specialise in boiler breakdowns and central heating systems, I enjoy solving complex faults and making sure systems are running safely and efficiently again, first time.

“In London properties, the most damaging leaks are the ones you can’t see. By the time a damp patch appears on a ceiling, the structural damage can already be significant. Finding it early – without demolition – is what this job is about.”

Oliver White

Senior Plumbing & Heating Engineer

28+ years experience – London

Gas Safe Registered
NVQ Level 3 Plumbing & Drainage
NVQ Level 3 Gas Maintenance & Breakdown
With over 28 years in the trade, including more than 20 at British Gas, I focus on diagnosing the root cause of issues quickly, from boiler faults to hidden leaks – so customers get a proper, long-term fix without unnecessary work.

“On an urgent call, the first thing I do is help the homeowner find and shut off the stopcock while I’m on my way. That one step stops the damage spreading and saves serious money. It only takes 10 minutes on the phone.”

What to expect

What every 0800 Homefix plumber brings to your door

Every engineer arrives with a fully stocked van, carries Gas Safe ID you can inspect, and introduces themselves by name before entering your property. They explain what they have found and what the fix involves before starting any work – and they leave your property clean and tidy when they are done.

  • Gas Safe ID carried and shown on request before any gas work
  • Fixed quote agreed before any work begins - no surprises
  • Fault diagnosed and explained in plain language
  • Shoe covers worn and workspace left clean and tidy
  • Written confirmation of 12-month workmanship guarantee on completion
  • Gas Safe documentation provided after every gas job, automatically

All engineers carry Gas Safe ID and are DBS checked. You can verify any engineer’s Gas Safe registration independently at gassaferegister.co.uk before work begins.

Responsibilities

How Pressure Testing Leak Detection Works

Pressure testing is a controlled diagnostic method based on a simple principle: if a sealed section of pipework is holding pressure, it has no leak. If the pressure drops, water or gas is escaping somewhere within that section. Here is how the process works in practice.

The Test Procedure

The section of pipework under investigation is isolated by closing the isolation valves at either end of the circuit. A pressure gauge and a test pump are connected to the system at a suitable access point. The system is pressurised to a test pressure appropriate for the pipe type, diameter and expected working pressure.

The system is then left undisturbed for a stabilisation period. This allows the temperature of the water or air in the pipe to equalise and any temporary pressure increases from the pump to settle. After stabilisation, the gauge reading is recorded as the start pressure.

The test period begins. A typical residential plumbing or heating test runs for 60 minutes. At the end of the period, the gauge is read again. If the pressure has dropped by more than the acceptable tolerance for the system type, a leak is confirmed in the isolated section.

What a Pressure Test Tells You

  • Whether a leak is present in the tested section of pipework
  • Whether a leak is present in the tested section of pipework
  • Which section of the system is affected when multiple circuits are tested
  • Whether a completed repair is holding correctly under working conditions

What a Pressure Test Does Not Tell You

A pressure test confirms that a leak is present and identifies the affected circuit. It does not give you a precise physical location within that circuit. That is what the follow-on investigation methods are for.

Once a pressure test has confirmed a fault and narrowed it to a specific section of pipework, we use acoustic listening equipment to detect the sound of escaping water, thermal imaging to identify temperature anomalies caused by moisture, or tracer gas to trace the exact exit point of the leak within that section.

This is the correct sequence: pressure test first to confirm and isolate, follow-on detection second to locate precisely. Skipping the pressure test and going straight to thermal imaging or tracer gas on an entire system wastes time and increases the risk of missing the source.

When Pressure Testing Is the Right Starting Point

  • Water bill has increased with no obvious cause
  • Suspected leak in a section of concealed pipework
  • Pre-investigation step before trace and access work
  • Post-repair verification that a repaired section is holding
  • New installation testing before walls are closed up

Systems

Systems We Pressure Test

Different systems require different test pressures, different durations and different procedures. Our engineers are familiar with the requirements for all of the following.

Why Is It Important to Use Gas Safe Registered Engineers for Boiler Repairs

Central Heating Systems

A sealed central heating system that keeps losing pressure is one of the most common diagnostic challenges we deal with. The system may be losing water through a micro-leak in the pipework, a failed pressure relief valve, a faulty expansion vessel or a leaking heat exchanger in the boiler. A pressure test on the heating circuit, carried out with the boiler isolated, tells us whether the loss is in the pipework or in the boiler itself. We test heating circuits at 1.5 to 3 bar depending on the system specification.

New Installations Before Closing In

Pressure testing new pipework before walls are plastered or floors are screeded is both good practice and a requirement under many building regulations and insurance policies. A failed joint that goes undetected at installation stage can cause years of concealed leakage before it becomes visible. We carry out pre-closure pressure tests for builders, homeowners undertaking extensions, and bathroom or kitchen installation projects where the pipework will be concealed after completion.

Cold and Hot Water Supply Pipes

Cold water supply pipes run at mains pressure, typically 1 to 3 bar in London properties. Hot water circuits in combi and system boiler installations operate within similar ranges. A pressure test on a supply circuit confirms whether the pipe run from the meter or from the cylinder is losing water. In properties with a history of pinhole corrosion or where original lead or steel pipe is still in use, pressure testing is a fast way to confirm whether a suspected pipe section is failing.

Post-Repair Verification Tests

After any leak repair involving concealed pipework, a pressure test confirms that the repaired section is holding before the access hole is made good. This is standard practice in any reputable repair and essential when the repair is part of an insurance claim. Without a documented post-repair pressure test, an insurer has no confirmed proof that the repair was successful. We carry out post-repair tests as a matter of course and include the result in all written repair reports.

Underfloor Heating Circuits

Underfloor heating pipes are typically buried in screed at depths of 50mm to 75mm. When a circuit starts losing pressure, finding the exact failure point without a reliable test result is time-consuming and risks unnecessary screed removal. We pressure test individual underfloor circuits via the manifold connections, isolating each loop in turn to identify which specific circuit is affected before any screed investigation begins. Test pressures for underfloor systems typically run between 4 and 6 bar, above working pressure, to demonstrate the integrity of the pipe under stress.

Gas Pipework

Gas tightness testing is a specific form of pressure testing carried out on internal gas pipework. It is a legal requirement under Gas Safe standards before any gas appliance is connected or reconnected, and after any gas pipe work is carried out. Our Gas Safe registered engineers carry out gas tightness tests using a manometer to detect any pressure loss in the internal gas supply system. A gas tightness test is always the first step in our gas leak investigation process. See our Gas Leak Detection and Repair page for full details.

Our rates

Straightforward Pricing. No Surprises.

We quote before we start. When we arrive, the engineer assesses the job and confirms the cost before any work begins.

No call-out fee

We do not charge a call-out fee. You pay for the first hour of labour, which covers the engineer’s arrival, the pressure test setup and procedure, diagnosis and the job itself. If further investigation or repair is needed beyond the first hour, we provide a fixed price quote before any additional work begins.

Documented Test Report

The written pressure test report, including start and end pressures, test duration and conclusion, is included as part of every investigation at no extra cost. This report is accepted by the major UK insurers for trace and access claims.

Out-of-Hours Visits

A small uplift applies for evening, weekend and bank holiday visits. This is always confirmed before the engineer travels and detailed in full on our rates page.

View Our Full Rate Card

Our full pricing details including the first-hour rate and out-of-hours uplift are on our rates page. View our rates before you call so you know exactly what to expect.

Want to see our full rate card?

Hourly rates, emergency callout charges, and out-of-hours uplifts, all published clearly before you book.

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Insurance

Pressure Testing and Insurance Claims

If you are making a buildings insurance claim for a hidden leak, the pressure test result is one of the first pieces of documentation your insurer will expect to see. It provides objective evidence that a leak was confirmed in a specific section of the system before any access work was authorised.

Our pressure test reports include the date, the engineer’s name and Gas Safe registration number where applicable, the system section tested, the test pressure, the test duration, the start and end pressure readings, and the conclusion. This format meets the documentation requirements of the major UK insurers.

Where a pressure test is part of a larger trace and access investigation, the test result is incorporated into the full trace and access report. For full details on insurance documentation and the trace and access process, see our Trace and Access service page.

Customer reviews

What Our Customers Say

Good

4.4 | 77 reviews

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Common questions

Frequently Asked Questions
About Our Pressure Testing Service

Some questions homeowners, landlords, and tenants typically ask before booking one of our plumbers in London.

What does your pressure testing service involve?

We isolate the section of pipework under investigation, connect a pressure gauge and test pump at a suitable access point, and pressurise the system to the appropriate test pressure for the system type. After a stabilisation period, we record the start pressure and monitor it for the test duration – typically 60 minutes for a residential plumbing or heating circuit. If the pressure drops by more than the acceptable tolerance, a leak is confirmed in the tested section. We then move to follow-on detection methods to pinpoint the exact location.

Do you charge a call-out fee for pressure testing?

No. We do not charge a call-out fee. You pay for the first hour of labour, which covers the engineer’s arrival, the test setup and the test itself. If follow-on investigation or repair work is needed beyond the first hour, we provide a fixed price quote before any additional work begins. Out-of-hours callouts carry a small uplift for evenings, weekends and bank holidays, which is confirmed when you call. Full details are on our rates page.

How long does a pressure test take?

The test period itself is typically 60 minutes for a standard residential plumbing or heating circuit. Allow an additional 30 to 45 minutes for setup, connection, pressurisation and the stabilisation period before the test begins. For a property with multiple circuits to test, the total time increases proportionally. For a typical central heating investigation in a three-bedroom house, allow 2 to 3 hours for a thorough section-by-section test.

Will a pressure test tell you exactly where the leak is?

A pressure test confirms a leak is present in the tested section of pipework and gives an indication of severity. It does not give you an exact physical location within that section. For that, we use acoustic listening equipment, thermal imaging or tracer gas after the pressure test has identified the affected circuit. These follow-on methods locate the failure point precisely, which is what determines where any access work needs to happen.

Can you pressure test underfloor heating systems?

Yes. We pressure test individual underfloor heating circuits via the manifold connections. By isolating each loop in turn and testing at above working pressure, we identify exactly which circuit has failed before any screed investigation begins. This step is essential for underfloor heating work because screed removal is expensive and disruptive, and starting it without a confirmed test result risks opening the wrong area.

Do you carry out pressure tests after a repair?

Yes. A post-repair pressure test is standard practice after any repair to concealed pipework. It confirms the repaired section is holding under working conditions before the access hole is made good. Without a documented post-repair pressure test, there is no confirmed evidence the repair was successful. We include the post-repair test result in all written repair reports as standard.

Will you provide a written report for my insurance claim?

Yes. Our pressure test reports include the date, the engineer’s Gas Safe registration number, the section tested, the test pressure, the duration, the start and end pressure readings, and the conclusion. This report meets the documentation requirements of the major UK insurers for trace and access claims. If you are progressing an insurance claim, have your claim reference number ready when you call so we can prioritise the visit.

Do you carry out the repair as well as the pressure test?

Yes. Once the pressure test and follow-on detection have confirmed the location of the fault, we carry out the repair in the same visit in most cases. A fixed price is agreed with you before any access or repair work starts. After the repair is complete, we carry out a second pressure test to confirm the fault has been resolved. One visit, one report, one invoice.

Coverage

Complete London Coverage

Our plumbers in London operate across all Greater London boroughs and areas within the M25. We have engineers based throughout the city so response times are fast wherever you are.

East London

E, IG, RM postcodes

Barking & Dagenham, Hackney, Havering, Newham, Redbridge, Tower Hamlets, Waltham Forest

West London

W, UB, TW postcodes

Brent, Ealing, Hammersmith & Fulham, Harrow, Hillingdon, Hounslow, Richmond upon Thames

North London

N, NW, EN postcodes

Barnet, Camden, Enfield, Haringey, Islington

South London

SE, SW postcodes

Bromley, Croydon, Greenwich, Lambeth, Lewisham, Merton, Southwark, Sutton, Wandsworth

Central London

WC, EC postcodes

City of London, Kensington & Chelsea, Westminster

South East England & Other

Home Counties / North London Fringe

AL, HP, SG, EN 

St Albans, Hemel Hempstead, Stevenage, (London North crossover)

Kent

DA, ME, TN, CT    

Dartford, Medway, Tonbridge, Canterbury

Surrey

GU, KT, RH 

Guildford, Kingston upon Thames, Redhill

Thames Valley

SL, RG, OX

Slough, Reading, Oxford

South Coast

BN, PO, SO

Brighton, Portsmouth, Southampton

Need to check if we cover your specific postcode?

Speak to our team who can confirm engineer availability. If you are in London (within the M25) or the home counties the short answer will likely be yes.
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From the 0800 Homefix blog

Guides and Advice

Our engineers write practical guides based on the plumbing issues they see most often across London properties. Whether you are dealing with a suspected leak, facing an insurance claim, or trying to understand what a repair involves before you call, these articles will help.
Can a Leaking Boiler Be Repaired_ Causes and Solutions Explained
What Equipment Do Plumbers Use to Detect Water Leaks Effectively?
June 6, 2025

Plumbers use a range of specialist equipment to detect water leaks accurately and non-invasively. The main tools include acoustic sensors and ground microphones to listen for escaping water, thermal imaging cameras to detect temperature anomalies caused by moisture, tracer gas to locate leaks in buried pipes, moisture meters to measure dampness levels, and pressure testing equipment to confirm pipe failure. Combining multiple methods ensures precise leak identification before any invasive repair work begins, minimising unnecessary damage to walls, floors, or ceilings.

Read More
Understanding What Is Included in a Boiler Service_ A Complete Guide
Plumber or Leak Detection Specialist: Who Should You Call First?
April 23, 2025

Call a plumber first for visible leaks such as dripping taps, burst pipes, or appliance faults. Call a leak detection specialist first when you suspect a hidden leak but cannot see one, especially if water bills have risen unexpectedly, damp patches have appeared, or water is running without any tap being open. Specialists use thermal imaging, acoustic sensors, and moisture meters to locate concealed leaks without destructive work. In many cases, both professionals work together: the specialist finds the leak, and the plumber carries out the repair.

Read More
How Tracer Gas Leak Detection Can Save You Time and Money
How Tracer Gas Leak Detection Can Save You Time and Money
June 13, 2024

Tracer gas leak detection uses a safe, non-combustible blend of hydrogen and nitrogen injected into a water pipe system to identify the precise location of a hidden leak. As the gas mixture escapes through the leak point, specialist equipment detects it at the surface, pinpointing the fault accurately. This method is non-invasive, highly accurate, and avoids unnecessary excavation or property damage. It is particularly effective for locating leaks in underground supply pipes, underfloor heating, and central heating systems, saving both time and repair costs.

Read More

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Get in touch

Boiler Losing Pressure? Suspected Leak? Let Us Test It Properly.

A pressure test carried out correctly tells you whether a leak is present, which part of the system is affected, and how significant the fault is – all before a single floor tile is lifted or a wall is opened. Call us and we will carry out the test and advise you on what happens next.

Gas Safe Registered | 1-Hour Emergency Response | No Call-Out Fee 

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