Landlord gas safety certificate (CP12): cost and rules

If you let a property in the UK that has any gas appliance or gas pipework, you must have a valid gas safety certificate. It is usually called a CP12, and its formal name is the Landlord Gas Safety Record. A Gas Safe registered engineer checks the gas appliances, pipework and flues every 12 months, and you give the tenant a copy within 28 days.

It costs £60 to £90 for a property with one appliance in 2026, a bit more with several appliances or in London. This guide covers who needs one, the rules that trip landlords up, and what actually gets checked.

Points to take away

• Every UK landlord with a gas appliance or gas pipework needs an annual CP12.
• Homeowners living in their own property do not need one.
• Cost is £60 to £90 for one appliance, plus about £10 to £15 per extra appliance.
• Give the tenant a copy within 28 days, and before any new tenant moves in.
• Renew within two months of expiry to keep the same anniversary date.

Reading time: about 6 minutes.

Who needs a CP12

You need one if you are a landlord and the property has gas. That means any of: a gas boiler, a gas hob or oven, a gas fire, a warm-air unit, or gas pipework, whether or not an appliance is connected to it. The duty falls on the landlord, or the letting agent if they manage the property and it is in the agreement.

It applies to houses, flats, rooms in a house in multiple occupation (HMO), holiday lets and most other residential tenancies. In an HMO, the landlord is responsible for appliances in the shared parts and any they provide in the let rooms.

You do not need one if you own and live in the property yourself, or if the property is entirely electric with no gas supply at all. A tenant’s own gas appliance, brought in by them, is checked but is their responsibility to maintain.

What a CP12 costs in 2026

Prices are for a Gas Safe registered engineer visiting a rented property. Add £15 to £30 for London and the South East.

Booking the CP12 and an annual boiler service together usually costs less than two separate visits, and keeps the manufacturer warranty valid.

The rules landlords must follow

• Annual check. Every gas appliance and flue inspected every 12 months by a Gas Safe registered engineer.
• Give the tenant a copy. Within 28 days of the check for existing tenants, and to any new tenant before they move in.
• Keep records. Hold each certificate for at least two years.
• Use a registered engineer. They must be on the Gas Safe Register and qualified for the appliance types in the property. Ask to see the ID card.
• Act on faults. If the engineer flags an appliance as unsafe, it must be dealt with, not ignored.

The two-month rule, explained

Landlords lose days off the clock by getting the check done too early. Here is how it works.

If your certificate expires on 1 March and you renew it any time in January or February, the new certificate still runs to 1 March the following year. You keep your anniversary date and lose nothing.

Renew it in December, more than two months early, and the 12 months restart from the December check date. You have effectively shortened the cycle. So schedule the CP12 in the two months before expiry, not the moment you think of it.

What the engineer actually checks

For each gas appliance and the pipework and flues, the engineer checks:

• That the appliance is on the gas supply correctly and burning safely
• Gas pressure and the gas rate
• The flue draws combustion products out of the property properly
• Ventilation is adequate
• Safety devices work

The outcome for each appliance is recorded as safe to use, or given a fault classification. At Risk means a fault that could become dangerous. Immediately Dangerous means the appliance is unsafe now, and with your permission the engineer will disconnect it and cap it off. You then arrange the repair before it goes back into use.

A CP12 is not a boiler service

This catches a lot of landlords out. A CP12 checks that the gas appliances are safe. It does not clean the boiler, does not check its efficiency, and does not extend its working life.

A boiler service is the maintenance visit: casing off, components cleaned and inspected, a flue gas analyser reading taken, the service record stamped. It is what keeps the boiler reliable and the warranty valid. Our guide to what a boiler service costs and includes explains the difference in full. Many landlords sensibly book both on the same visit.

Penalties for letting without one

Letting a property with gas and no valid CP12 exposes you to:

• An unlimited fine and possible prosecution by the Health and Safety Executive
• Invalidated landlord insurance, so a gas-related claim is refused
• A blocked Section 21 notice, because you cannot serve a valid no-fault eviction without having met your gas safety duties

If a tenant is injured or worse by a gas fault in a property with no valid certificate, the landlord faces far heavier consequences, including corporate manslaughter charges in the most serious cases.

Booking your CP12

Use a Gas Safe registered engineer who does landlord work and can provide the certificate the same day. Book it in the two months before your current one expires.

Get free quotes from Gas Safe registered engineers covering your postcode, or browse the directory to find heating and gas companies registered in your area.