A Gas Safety Certificate (formally known as a CP12) is a legal document issued by a Gas Safe registered engineer after inspecting all gas appliances in a property. Here's everything you need to know.
Who needs a gas safety certificate?
Private landlords in the UK are legally required to have all rented properties with gas appliances inspected annually by a Gas Safe registered engineer. The certificate must be provided to tenants within 28 days of the check.
Homeowners are not legally required to have an annual gas safety check, but it is strongly recommended — particularly before selling a property.
What's inspected?
The engineer checks all gas appliances in the property — typically the boiler, gas fires, and gas hob. They inspect:
- Gas supply pipework
- Appliance operation and safety
- Flue condition and ventilation
- Gas pressure and flow
- Combustion analysis (CO check)
What happens if something fails?
If an appliance is deemed unsafe (an "Immediately Dangerous" or "At Risk" classification), the engineer is required to disconnect the appliance and clearly mark it as not to be used. A written explanation is provided to the tenant and landlord.
The penalty for landlords without a certificate
Failure to maintain an annual gas safety record is a criminal offence in the UK, with fines of up to £6,000 and potential imprisonment for serious breaches. It also invalidates any landlord insurance.