COST GUIDES
What's the cost to replumb a gas supply in 2026?
Updated 06/26
Cost to replumb a gas supply:
Gas supply replumbing typically costs £150–£800, with an average cost of around £375 for straightforward gas pipe upgrades
Replumbing to relocate boiler:
Pipework costs to relocate a boiler typically range from £400–£600
Good to know:
Older 15mm gas pipes often need upgrading to 22mm for modern combi boilers
Compliance:
All gas pipework installations or alterations must be carried out by a Gas Safe registered engineer
If you're replacing an older boiler, installing a modern combi boiler or relocating your existing boiler, you may discover that your gas pipework also needs upgrading.
Many older properties still have 15mm gas pipes, but modern boilers often require a larger 22mm supply pipe to operate safely and efficiently. In some cases, longer pipe runs may need even larger pipework.
In this guide, we'll explain how much gas supply replumbing costs, what affects the price, when a boiler relocation might require new pipework and what to expect from the installation process.
Cost to replumb a gas supply
Most gas supply replumbing projects cost between £150and £800, with many homeowners paying around £375for a straightforward upgrade.
If you're moving a boiler at the same time, costs can rise to around £400–£600due to the additional pipework, flue alterations and installation work involved.
| Cost provided item | Range - Low | Range - High | Average cost |
|---|---|---|---|
| Cost to replumb gas supply | £150 | £800 | £375 |
| Replumbing to relocate your boiler | £400 | £600 | £500 |
| Last updated: June 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
The final price will largely depend on the length of pipe required, whether floors or walls need opening up and how easy the existing pipework is to access.
Get a quote for gas supply replumbing
Whether you're upgrading pipework for a new boiler or rerouting an existing gas supply, it's always worth comparing a few quotesbefore work begins.
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Gas supply replumbing costs at a glance
Average gas supply replumbing cost: £375
Typical cost range: £150–£800
Pipework for boiler relocation cost: £400–£600
Flue extension cost: £75–£125per metre
Gas pipe rerouting cost: £45–£85per metre
Magnetic filter cost: £150–£225
What is gas supply replumbing?
Gas supply replumbing involves replacing, upgrading or rerouting the pipe that carries gas from your meter to your boiler or other gas appliances.
One of the most common reasons for this work is a boiler replacement.
Older systems were often installed with 15mmgas pipes, whereas many modern combi boilers require a 22mmsupply pipe. In some larger homes or longer pipe runs, 28mmor even 35mmpipework may be needed.
How do you know if you need your gas supply replumbed?
For many homeowners, the need for gas supply replumbing only comes to light when they're getting quotes for a new boilerand an engineer spots that the existing pipework isn't large enough for the new system.
It's often not the boiler that's causing the issue, but older pipework that's too small to safely deliver enough gas to modern appliances.
Some upgrades are relatively straightforward, but longer pipe runs or difficult access can increase costs significantly.
Boiler relocation costs
If you're moving your boiler to a different room, you'll often need additional pipework as part of the project.
This is common when:
Moving a boiler from a kitchen into a utility room
Relocating a boiler into a garage
Reconfiguring a property during a renovation
Creating additional kitchen cupboard space
Relocating a boiler typically costs between £400–£600, although the final cost will depend on the amount of new pipework required.
Typical additional costs for a boiler relocation
Flue extensions: Extending or rerouting a flue typically costs £75–£125per metre
Pipework alterations:Connecting the boiler to existing heating and water systems typically costs £400–£600
Gas pipe rerouting:Rerouting gas pipes generally costs £45–£85per metre
Magnetic filters:Adding a magnetic filter typically costs £150–£225
One thing many homeowners underestimate is how disruptive moving a boilercan be compared with simply replacing one in the same location.
Depending on where the new boiler is being installed, floors may need lifting, pipework may need extendingand the heating and hot water could be unavailablewhile the work is carried out.
In many homes, the disruption only lasts a day, but it's worth planning ahead if you'll be without heating, hot water or cooking facilities during the work.
Getting gas into a property for the first time
If you're researching the cost of installing a gas lineor arranging a new gas supply to a property, you'll need a mains gas connection before any internal gas pipework can be installed.
This situation is most common in:
Homes currently using oil heating
Electric-onlyproperties
Some self-build projects
Connection costs vary significantly depending on your location, how far you are from the nearest gas main and the requirements of the local gas network operator.
Who's responsible for installing a new gas supply to a property?
One thing that's often misunderstood is who actually carries out the connection.
The external connection to the mains gas network is usually completed by your local gas network operator, not the engineer installing your boiler.
Once the connection is in place, you'll still need a gas meter, internal pipework and a registered gas engineer to complete the installation inside your property, including radiators or central heating pipework, where applicable.
This is why the total cost of getting gas into a home can end up being significantly higher than the connection fee alone.
Planning for a full gas installation project? Our cost guides can help understand the numbers involved: take a look at our full gas installation cost guide, new boiler cost guide and central heating installation cost guide.
What affects the cost of replumbing a gas supply?
Two people can receive very different quotes for what sounds like the same job. That's because the cost isn't just about the pipe itself, it's largely driven by how far the new pipe needs to run and how easy it is to access the existing pipework.
The main factors that tend to affect the cost of gas supply replumbing include:
Pipe run length:The further the pipe needs to travel between the meter and boiler, the more materials and labour will be required
Pipe diameter:Modern boilers often require larger pipe diameters than older systems
Concealed or exposed pipework: Running pipes beneath floors or inside walls is usually more labour-intensive than surface-mounted pipework
Property layout:Flats, extensions and properties with limited access can increase installation complexity
Regional labour rates:Gas Safe engineers in London and the South East typically charge higher rates than the UK average
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Additional costs to budget for
Alongside the gas pipe upgrade itself, you may need to budget for:
Flue extensions
Making good walls or floors after pipe installation
Magnetic filters
Additional pipe boxing or concealment work
Always ask whether these items are included in the quoteor charged separately.
What's included in a Gas Safe engineer's quote?
A quote for replumbing a gas supply will typically include:
Removal of old pipework where required
Supply and installation of new gas pipework
Pressure testing
Safety checks
Commissioning and testing
Gas Safe certificationwhere applicable
It won't usually include redecoratingor repairing wallsand flooringdisturbed during the work, so it's worth checking this before work begins.
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How long does it take to replumb a gas supply?
A straightforward gas pipe upgrade typically takes between half a day and a full day.
More complex projects involving concealed pipework, boiler relocation or long pipe runs can take one to two days.
One practical thing to plan for is that your gas supply will normally be isolated while work is carried out. Depending on your setup, this may temporarily affect your heating, hot water and cooking appliances.
Do you always need a Gas Safe engineer?
Yes. Any work involving gas pipework must be carried out by a Gas Safe registered engineer.
This isn't just best practice, it's a legal requirement under the Gas Safety (Installation and Use) Regulations.
Gas work carried out by someone who isn't Gas Safe registered can create serious safety risks and may invalidate your home insurance.
Tips for keeping gas supply replumbing costs down
Get several itemised quotes
Keep pipe runs as short as practical
Consider surface-mounted pipework where appropriate
Combine the work with a boiler replacementproject
Check whether making good is included
Gas supply replumbing checklist
When should you speak to a Gas Safe engineer?
If you're replacing a boiler, moving a boiler, renovating your homeor experiencing gas pressure issues, it's worth speaking to a qualified gas engineerearly in the process.
A quick survey can often identify whether pipe upgrades are needed before installation work begins, helping you avoid unexpected costs later.
Find a Gas Safe engineer near you
Gas supply replumbing isn't a job to leave to chance. Correctly sized and installed pipework helps ensure your boiler operates safely, efficiently andin line with current regulations.
Compare quotesfrom checked Gas Safe engineers working in your areaand find the right professional for your project.
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Gas supply replumbing FAQs
No. If your existing pipework is already the correct size and can deliver sufficient gas pressure to the new boiler, it may not need replacing. A registered gas engineer will assess your existing pipework as part of the quotation process.
The cost depends on how far the pipe needs to be moved, whether new pipework is required and how easy the existing pipework is to access. If walls, floors or units need to be altered to accommodate the new route, costs can increase. All gas pipework alterations must be carried out by a Gas Safe registered engineer.
The gas supply pipe from the mains network to the meter is normally the responsibility of the local gas network operator. Pipework running from the meter into your home is generally the homeowner's responsibility.
A straightforward gas pipe replacement or upgrade typically takes between half a day and a full day. More complex projects involving concealed pipework, boiler relocation or longer pipe runs can take one to two days.
It depends on your circumstances. For many people switching from electric or oil heating, mains gas can offer lower running costs. However, you'll need to factor in the cost of the connection itself, along with any boiler, pipework and heating system installation costs.
Capping a gas pipe is usually a relatively small job carried out when removing an appliance or decommissioning part of a gas supply. The exact cost will depend on the complexity of the work and your engineer's rates. As with all gas work, it must be carried out by a Gas Safe registered engineer.
No. Gas pipework must only be installed, altered or repaired by a Gas Safe registered engineer. Attempting DIY gas work is illegal and can create serious safety risks for you, your family and your property.
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