Gas Tightness Testing After 1 October 2026, a Safety Warning
Gas Tightness Testing After 1 October 2026 Is Now Stricter
Important gas safety update for homeowners and landlords. New rules for gas tightness testing came into force on 1 October 2026, and they could affect your home the next time a Gas Safe engineer works on your gas supply. At T J Plumbing Shefford, we want every customer across Bedfordshire and Hertfordshire to understand what has changed, why it matters and what it could mean for you.
The change comes from the updated industry standard, IGEM/UP/1B Edition 4, which sets out how gas tightness testing must be carried out on small domestic gas installations. Below, we explain the new requirements in plain English so you know exactly what to expect.
Your Guide to the New Gas Testing Rules
- What Has Changed With Gas Tightness Testing?
- How the Old Rules Compared to the New Ones
- Pipework or Appliance? Why the Difference Matters
- This Doesn’t Just Affect New Boiler Installations
- What Does Stricter Gas Tightness Testing Mean for You?
- A Note for Landlords in Bedfordshire and Hertfordshire
- How to Prepare for Your Next Gas Visit
- Will This Cost Extra?
- Please Remember, These Are Industry-Wide Changes
- Gas Tightness Testing Questions We Are Often Asked
- Speak to Your Local Gas Safe Engineers
What Has Changed With Gas Tightness Testing?
A tightness test is a simple but vital safety check. Your engineer connects a pressure gauge to the gas installation, pressurises the system and then watches for any drop in pressure over a set period of time. A drop can point to gas escaping somewhere in the pipework, a fitting or an appliance.
IGEM/UP/1B Edition 4 was published in March 2026 and ran alongside the older Edition 3 for a six-month transition period. Edition 3 was withdrawn on 30 September 2026, so from 1 October 2026 every Gas Safe registered engineer must follow the new edition for gas tightness testing on small natural gas and LPG installations in homes.
How the Old Rules Compared to the New Ones
Previously, under certain conditions, a small pressure drop during a test could be accepted, provided it stayed within the permitted limits and there was no smell of gas. In many homes, that meant the engineer could record the result and carry on with the job without any further investigation.
The rules have now changed. Under the updated standard, if a perceptible pressure drop is detected, the engineer must now establish whether it is coming from the gas pipework or from an existing appliance. The permitted limits have also been reworked, so they are now based on the volume of the installation being tested rather than mainly on the size of the gas meter. In short, gas tightness testing has become more thorough and less forgiving.
| What is checked | Before (Edition 3) | Now (Edition 4) |
|---|---|---|
| Small pressure drop | Could be accepted within permitted limits | Must be traced to the pipework or an appliance |
| Gas pipework | A small drop could pass if there was no smell of gas | No perceptible pressure loss allowed |
| Existing appliances | Usually tested along with the pipework | May still pass within the permitted limits |
| Permitted limits based on | Mainly the size of the gas meter | The volume of the installation tested |
| Dates | Withdrawn on 30 September 2026 | Mandatory from 1 October 2026 |
Pipework or Appliance? Why the Difference Matters
This is the heart of the change to gas tightness testing, and it is worth understanding clearly:
- Existing appliances: a small pressure drop from an existing appliance may still be acceptable within the permitted limits.
- Installation pipework: the gas pipework itself must pass a tightness test with no perceptible pressure loss at all.
To find out where a drop is coming from, your engineer may need to isolate appliances and test the system again. That can add a little time to a visit, but it gives a much clearer picture of the condition of your gas supply. If the pipework fails, it stays failed until the fault is found and fixed. There is no option to fall back on the older, more relaxed criteria.
This Doesn’t Just Affect New Boiler Installations
Gas tightness testing is part of many everyday jobs, so the new rules apply whenever a test is required. That includes:
- Annual boiler servicing, where a tightness test is carried out as part of your yearly boiler servicing visit
- Landlord gas safety checks on rented homes
- Boiler replacements and new installations, as covered on our boiler installation page
- Replacing gas valves, components or other parts where testing is needed during boiler repairs
- Alterations or repairs to existing gas pipework, such as moving a cooker or extending a supply
- Any other gas work that requires gas tightness testing
Whether you use natural gas or LPG, the same stricter approach now applies to your installation.
What Does Stricter Gas Tightness Testing Mean for You?
Your heating system may have worked perfectly for years, with no smell of gas and no obvious problems. However, under the new testing requirements, our engineers may discover an issue with existing gas pipework that previously would not necessarily have needed further investigation.
This could mean additional work is needed to make your gas installation safe before we can continue with the job we came to do. A pressure loss small enough to pass in the past may now need tracing and repairing.
Common Causes Found During Testing
- Older compression fittings that have loosened slightly over time
- Worn joints or seals on pipework hidden under floors or behind kitchen units
- Corrosion on older steel or copper pipe runs
- Gas cocks or isolation valves that are no longer sealing fully
None of these may have caused a noticeable problem before. Under the stricter gas tightness testing rules, they now need to be found and put right so your installation can be confirmed as safe.
A Note for Landlords in Bedfordshire and Hertfordshire
If you let a property, you must arrange an annual gas safety check by a Gas Safe registered engineer under the HSE landlord gas safety rules. Where gas tightness testing forms part of that check, the new standard applies in full.
We recommend booking your check a little earlier than usual. Leaving some time between the visit and your certificate deadline means any pipework repairs can be completed without putting your tenants, or your paperwork, at risk.
How to Prepare for Your Next Gas Visit
A little preparation can help your appointment run smoothly under the new rules:
- Clear access to your gas meter, boiler and any appliances such as hobs or gas fires
- Let us know about any changes made to your gas pipework since our last visit, such as a new kitchen or extension
- Allow a little extra time in case appliances need to be isolated and tested separately
- Mention any concerns, even a faint smell of gas that comes and goes
Telling us about older pipework or previous alterations helps our engineers plan the gas tightness testing properly and reduces the chance of a second visit.
Will This Cost Extra?
If we discover an issue during gas tightness testing, we will always:
- Explain clearly what is wrong and where the pressure loss is coming from
- Talk you through your options
- Provide a quotation for any additional repairs required before any work begins
Many faults are small and quick to put right. Where a larger job is needed, such as replacing an old section of pipework alongside a new boiler, you can request a boiler quote or explore boiler finance options to spread the cost. Customers on one of our boiler care plans also benefit from regular checks that help spot problems early.
Please Remember, These Are Industry-Wide Changes
These rules have not been introduced by T J Plumbing Shefford. They apply to every Gas Safe registered engineer carrying out gas tightness testing on domestic installations.
We understand it can be frustrating to be told that something needs repairing when it has worked without problems for years. Our engineers are simply following the latest gas safety requirements to keep you and your family safe. Even a very small gas escape can matter, and it is far better to find it during a routine visit than after something goes wrong.
Gas Tightness Testing Questions We Are Often Asked
Is my home dangerous if it fails a tightness test?
A failed test means the installation cannot be confirmed as gas tight. Your engineer will follow Gas Safe procedures, which may include turning off part or all of the supply until the fault is fixed. They will explain everything before taking any action.
Will every boiler service now take longer?
Most visits will run as normal. Extra time is usually only needed if a pressure drop is seen and the engineer has to track down its source by testing sections of the system separately.
Does gas tightness testing apply to LPG homes?
Yes. The standard covers small natural gas, LPG and LPG/Air installations, so our LPG customers across rural Bedfordshire and Hertfordshire are included.
How can I check my engineer is qualified?
Always ask to see their Gas Safe ID card, or check the register online. You can view our Gas Safe registration details at any time.
Speak to Your Local Gas Safe Engineers
T J Plumbing Shefford Ltd is a Gas Safe registered business and a Worcester Bosch Accredited Partner, installing and maintaining gas, LPG and oil boilers across Bedfordshire and Hertfordshire. If you have questions about gas tightness testing, or you would like to book work with our team, please get in touch with us.
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