Gas Safety Certificate (CP12): The Complete Landlord Guide (2026)

If you let a property with gas appliances, a Gas Safety Certificate — officially called a CP12 — is a legal requirement. This guide explains everything you need to know: what it covers, how much it costs, how often you need one, and what happens if your certificate lapses.

What is a Gas Safety Certificate (CP12)?

A CP12 is an official record of a Gas Safety inspection carried out by a Gas Safe registered engineer. It confirms that all gas appliances, flues, and pipework in a rented property are safe and operating correctly.

The document is issued after inspection and lists every gas appliance checked, the results, and the engineer's Gas Safe registration number. It must be given to existing tenants within 28 days of the inspection, and to new tenants before they move in.

Is a Gas Safety Certificate a legal requirement?

Yes. Under the Gas Safety (Installation and Use) Regulations 1998, landlords in England, Scotland, and Wales must:

• Have a Gas Safety check carried out annually by a Gas Safe registered engineer
• Give tenants a copy of the certificate within 28 days of the check
• Give new tenants a copy before they move in
• Keep records of checks for at least 2 years

Failure to comply is a criminal offence. The Health and Safety Executive (HSE) can prosecute landlords, and penalties include unlimited fines and up to 6 months' imprisonment. Your insurance may also be void if you don't hold a valid certificate.

How much does a CP12 inspection cost?

A Gas Safety Certificate inspection typically costs £60–£120 depending on your region and the number of appliances. London and the South East tend to be at the higher end. Properties with multiple gas appliances (boiler, hob, gas fire) may cost slightly more.

On EzeAla Fix, you can post the job and receive fixed-price quotes from Gas Safe registered engineers near your property. Payment goes into escrow and releases only after you confirm the certificate has been issued.

What does the inspection cover?

The Gas Safe engineer will check and test:

• All gas appliances (boiler, hob, oven, gas fire, etc.)
• Gas pipework and connections
• Flues and ventilation
• Safety devices (pressure relief valves, etc.)
• Gas pressure and operating conditions

If any appliance fails the inspection, the engineer will advise on remedial works. Unsafe appliances must be disconnected. You will receive a certificate only once all appliances pass (or unsafe ones are isolated).

How often do I need a Gas Safety Certificate?

Annually. The inspection must be carried out every 12 months. You can arrange it up to 2 months early without losing the existing certificate date — so if your certificate expires in December but you arrange the inspection in October, the new certificate will still expire the following December, not October.

EzeAla Fix tracks Gas Safety expiry dates per property and sends you reminders at 60 and 30 days before expiry, so certificates never lapse by accident.

What happens if my Gas Safety Certificate lapses?

A lapsed certificate puts you in breach of your legal obligations immediately. You cannot let the property (or continue to let it) without a valid certificate. Enforcement action from the HSE, council, or your mortgage lender can follow.

If a tenant is injured due to a gas appliance fault and you don't hold a valid certificate, you face significant civil and criminal liability. Don't let it lapse.