Quick Answer
A gas safety certificate (CP12) in the UK costs £60–£120 in 2026. Landlords are legally required to obtain one every year. The inspection covers all gas appliances and pipework and takes 30–90 minutes.
If you're a landlord in the UK, the annual gas safety check is one of your most important legal obligations — and one where the consequences of non-compliance are severe, including criminal prosecution. In 2026, understanding exactly what a gas safety certificate costs, what it covers, and what happens if an appliance fails is essential knowledge for any property owner.
Even for homeowners (who are not legally required to commission annual gas safety checks), understanding what is involved helps you make informed decisions about the safety of your boiler, cooker, and any other gas appliances. This guide covers the full picture — from who carries out the check to what happens when a fault is found.
In this guide
What Is a Gas Safety Certificate (CP12)?
A gas safety certificate — formally called a Gas Safety Record and sometimes referred to by its form number, CP12 — is the document issued by a Gas Safe registered engineer after completing a gas safety inspection of a property. The document confirms that all gas appliances, pipework, and flues in the property have been inspected and are safe to use.
The certificate records: the date of inspection, the appliances inspected (make, model, location), the results of each test, any faults found, and whether the appliances are "safe to use" or "immediately dangerous / at risk." A copy must be given to the tenant within 28 days of the inspection.
Only an engineer registered with the Gas Safe Register can legally carry out gas work or issue a gas safety certificate in the UK. Always verify the engineer's Gas Safe registration before allowing them to work — check at gassaferegister.co.uk or ask to see their Gas Safe ID card. See our guide on what to look for in a Gas Safe engineer for a full checklist.
Who Needs a Gas Safety Certificate?
| Property Type | Legal Requirement? | Frequency |
|---|---|---|
| Private rented residential property | YES — legally required | Every 12 months |
| HMO (houses in multiple occupation) | YES — legally required | Every 12 months (stricter enforcement) |
| Commercial premises with gas | YES — legally required | Every 12 months |
| Owner-occupied home | No legal requirement | Recommended every 2–3 years |
| New build (on handover) | YES — builder must provide | One-off on completion |
Landlords' legal obligations under the Gas Safety (Installation and Use) Regulations 1998 (as amended):
- Commission an annual gas safety check from a Gas Safe registered engineer
- Keep a record of the check for at least 2 years
- Give a copy of the gas safety record to existing tenants within 28 days of the check
- Provide new tenants with a copy before they move in
- Make repairs or upgrades required by the engineer within the timeframes specified
Failure to comply with these obligations is a criminal offence under the Gas Safety (Installation and Use) Regulations, carrying fines and potential imprisonment. It also invalidates your landlord insurance and could result in significant civil liability if a tenant is harmed.
What Is Checked During a Gas Safety Inspection?
A Gas Safe engineer carrying out a landlord safety check will inspect all gas appliances and pipework visible within the property. A typical inspection covers:
| Item Checked | What the Engineer Tests |
|---|---|
| Boiler / central heating | Ignition, combustion, flue spillage test, gas pressure, safety devices |
| Gas cooker / hob | Ignition, flame pattern, gas tightness, flexible hose condition |
| Gas fire / room heater | Combustion analysis, flue flow test, ventilation check |
| Gas pipework (visible) | Pressure test, corrosion, joints, accessibility |
| Flues and ventilation | Clearance, condition, termination point, obstructions |
| Emergency controls | Location and operation of gas isolation valve |
The inspection does not include a full boiler service — that is a separate, more comprehensive procedure. The gas safety check confirms the appliances are operating safely and within defined parameters; a full boiler service additionally cleans components, checks heat exchangers, and replaces wear parts. Most engineers offer to combine both in a single visit, which is more cost-effective. For more on boiler costs, see our guide on how much a new boiler costs in the UK.
How Often Is a Gas Safety Certificate Needed?
For landlords, the law is clear: a new gas safety check must be carried out every 12 months. However, since 2018 there is a useful provision: if the previous check was carried out in the last 10–12 months, the new check can be done up to 2 months early and the 12-month expiry date is carried forward from the original expiry (not the new check date). This means you can renew slightly early each year without losing the benefit of your renewal window.
For owner-occupiers, there is no legal obligation to have an annual gas safety check. The Health and Safety Executive (HSE) recommends having all gas appliances serviced annually by a Gas Safe registered engineer, but this is guidance rather than law. In practice, most homeowners get their boiler serviced annually (which includes a safety check) and may not have other appliances checked unless concerns arise.
What Happens If You Fail a Gas Safety Inspection?
Gas Safe engineers classify faults into three categories when an appliance or installation fails:
- Immediately Dangerous (ID)A fault where there is an immediate risk to life. The engineer will isolate the appliance and label it — it must not be used until repaired by a Gas Safe engineer and re-tested. Examples: carbon monoxide emission in a confined space, major gas leak, no flue.
- At Risk (AR)A fault that does not pose an immediate danger but could become dangerous. The appliance can continue to operate temporarily, but the fault must be repaired within a defined timescale. Examples: inadequate ventilation, slightly high CO reading.
- Not to Current Standards (NCS)An appliance or installation that does not comply with current standards but is not a safety risk. No immediate action required but should be rectified at the next available opportunity.
For landlords, if an appliance is classified ID or AR and is isolated, it cannot be used until repaired. You must arrange repairs by a Gas Safe engineer promptly. For more detail on what to look for when choosing a gas engineer, see our guide on what to look for in a Gas Safe engineer. For advice on choosing the right boiler if a replacement is required, see our guide on how to choose the right boiler for your home.
Frequently Asked Questions
What is the difference between a gas safety certificate and a boiler service?+
A gas safety check (CP12) is a statutory safety inspection covering all gas appliances, pipework, and flues. It confirms they are safe and operating within defined parameters. A boiler service is a maintenance procedure that additionally cleans the heat exchanger, checks burner efficiency, inspects the flue internally, and replaces any worn parts. Most engineers offer both in a combined visit for £80–£150.
Can a tenant refuse access for a gas safety check?+
Tenants must not unreasonably refuse access for a landlord's annual gas safety check. If a tenant refuses, the landlord should write formally to request access, document the refusal, and if necessary seek legal advice. The landlord must make every reasonable effort to comply with the legal obligation — but courts have recognised that a landlord cannot be expected to carry out the check if access is actively obstructed.
How long does a gas safety check take?+
A gas safety inspection for a typical one or two-bedroom flat with a boiler and gas hob takes 30–60 minutes. Larger properties with more appliances, or properties where access to appliances is difficult, take longer — up to 90 minutes.
Does a gas safety certificate cover the whole house?+
The gas safety certificate covers all gas appliances and visible pipework within the property. It does not cover underground gas mains, the meter (which is the gas supplier's responsibility), or appliances that are locked away or inaccessible during the visit. If an appliance cannot be accessed, it is noted on the certificate.
What if my property has no gas?+
If your property has no gas supply and no gas appliances, no gas safety certificate is required. You do not need to commission a check on electrical appliances or oil-fired heating — these are covered by separate inspection regimes. If you are unsure whether your property has gas, check for a gas meter (usually near the front of the property) or contact the gas emergency line (0800 111 999).
Is a gas safety certificate the same as a Gas Safe certificate?+
These terms are used interchangeably in everyday speech. The legal document is called a Gas Safety Record; it is issued by a Gas Safe registered engineer. 'CP12' is the form number historically associated with the document. All these terms refer to the same thing.
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