Landlord Gas Safety Certificate (CP12): The 2026 Guide
12 June 2026 · AgentCheck Editorial · 6 min read
Part of our UK Landlord Legal Guide
A gas safety certificate (CP12) confirms a property's gas appliances, flues and pipework have been checked as safe by a Gas Safe registered engineer. UK landlords must arrange one every 12 months, give the tenant a copy within 28 days (or before move-in), and keep records for two years. Failure risks an unlimited fine and prosecution.
Of all a landlord's safety duties, gas is the one with the highest stakes — and the one HMRC and the courts treat most seriously, because the risk is carbon monoxide poisoning and explosion. The rules are simple and non-negotiable: an annual check, a record to the tenant, and proof kept on file. This guide explains exactly what a CP12 is, who can issue one, the deadlines, and what happens if you let it lapse. It covers England and Wales; it is general guidance, not legal advice.
What a gas safety certificate (CP12) is
The CP12 — formally the Landlord Gas Safety Record — is the document a Gas Safe registered engineer issues after inspecting the gas installation in a rental property. It records that each gas appliance, the flue that carries fumes away, and the connecting pipework have been tested and found safe. The duty comes from the Gas Safety (Installation and Use) Regulations 1998, and it applies to every landlord who lets a property with a gas supply or gas appliances.
Who needs one and what gets checked
If your rental has any gas appliance — a boiler, hob, oven, gas fire or warm-air unit — or gas pipework, you need an annual check. The engineer inspects:
- Each gas appliance — that it burns correctly and is safe to use.
- Flues and chimneys — that combustion products vent safely outside.
- Gas pipework and connections — for tightness and correct installation.
- Ventilation and safety devices — that air supply and cut-offs work.
Appliances the tenant owns are their responsibility, but the connecting installation and any flue serving them remains yours. Only a Gas Safe registered engineer may carry out the work — always check the engineer's ID card and that their registration covers the appliance type.
How often: the 12-month rule
The check must be carried out at intervals of no more than 12 months. A useful concession: you can have the inspection done up to two months before the current certificate expires without losing your renewal date. So if your CP12 runs out on 1 September, booking the check any time from 1 July keeps the next anniversary on 1 September the following year — letting you build a safe buffer rather than risk a lapse. Set a reminder a month ahead; a gap of even a day means you are letting without a valid record.
Giving the certificate to your tenant
Issuing the CP12 is not enough — you must put it in the tenant's hands. The rules are strict:
| Situation | Deadline to provide the record |
|---|---|
| Existing tenant | Within 28 days of the check |
| New tenant | Before they move in |
| Tenancy of 28 days or less | Display a copy in the property |
Email is fine if the tenant agrees to receive documents electronically. Keep proof of when and how you sent it. If there is ever a dispute or a possession claim, you will want to show the record was given on time.
Keeping records
You must keep each gas safety record for at least two years. The record should show the date of the check, the property address, the engineer's name and Gas Safe registration number, a description of each appliance and flue checked, any defects found and any remedial action taken. Good landlords keep every CP12 indefinitely in a per-property file, because an unbroken history is powerful evidence of compliance if a dispute or claim ever arises.
What it costs and who can do it
A gas safety check typically costs in the region of £60–£90 for a single boiler, more where there are several appliances, and is often bundled with an annual boiler service at a modest extra cost. Only use a Gas Safe registered engineer — the legal successor to the old CORGI scheme — and verify their registration on the Gas Safe Register. Servicing and the safety check are different things: a service maintains the appliance, while the CP12 certifies safety, though many engineers do both in one visit.
Penalties for not having a valid CP12
Gas carries the heaviest penalties of any landlord safety duty. Letting without a valid gas safety record can mean an unlimited fine and, in serious cases, prosecution by the Health and Safety Executive carrying a possible prison sentence. Courts have handed down fines of tens of thousands of pounds for a single property. On top of that, a missing or expired CP12 will almost certainly invalidate your landlord insurance, so a gas incident could leave you personally liable. Against that, the cost of an annual check is trivial — this is the last duty any landlord should cut.
Gas safety after Section 21
Before 1 May 2026 the gas safety record was one of the documents that had to be in order for a Section 21 notice to be valid, and courts took a strict line on it. Section 21 was abolished in England on 1 May 2026, so that particular trap has gone. The duty itself has not changed: the annual check, the record and giving the tenant a copy are all still required, and the penalties above still apply. A complete file also puts you in a stronger position if you ever need to bring a Section 8 possession claim.
Your annual gas safety checklist
Stay compliant with a simple yearly routine:
- Book early — schedule the check up to two months before expiry to protect your renewal date.
- Use a Gas Safe engineer — verify their ID card and that it covers your appliance types.
- Serve the record — to existing tenants within 28 days, or to new tenants before they move in.
- File the CP12 — keep it at least two years, ideally for the life of the property.
- Act on defects — never let a property with an appliance the engineer has classed as unsafe.
If an appliance is found unsafe, the engineer may turn it off with your permission and you must arrange repairs before it is used again. Acting promptly protects your tenants and your position entirely.
Related guides
- Landlord legal requirements: the full 2026 compliance guide
- Landlord electrical safety: EICR requirements explained
- Deposit protection schemes compared
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