Landlord Gas Safety Certificate (CP12)
A landlord gas safety certificate, still widely called a CP12, is the record of the annual gas safety check every landlord must arrange. The Gas Safety (Installation and Use) Regulations 1998 require every gas appliance and flue a landlord is responsible for to be checked every 12 months by a Gas Safe registered engineer. This guide explains what is checked, the deadlines, and how it differs from a service.
What the law requires
| Duty | Rule |
|---|---|
| How often | Every 12 months, by a Gas Safe registered engineer |
| What is covered | Every gas appliance and flue the landlord is responsible for |
| Existing tenants | Given a copy within 28 days of the check |
| New tenants | Given a copy before they move in |
| Records | Kept for at least two years |
| Early checks | Since 2018, up to two months early without losing the anniversary date |
| CO alarms | Since 1 October 2022, in every room used as living accommodation with a fixed combustion appliance (gas cookers excepted) |
What the engineer checks
The check confirms that each appliance is safe to use at the time of the visit. For a boiler that means checking the gas tightness of the installation, the gas pressure and rate, that the flue is sound and clearing combustion products, that there is adequate ventilation, and that the safety devices work. Gas fires and cookers are checked in the same way. The engineer records each appliance, its location, the checks made and any defects, and that record is what tenants receive.
A safety check is not a service
This catches landlords out. The gas safety check confirms an appliance is safe; it does not include stripping and cleaning the boiler. A service is maintenance: the boiler is opened, cleaned, measured and adjusted, and it is what keeps the manufacturer's guarantee valid. That is why most landlords book both on one visit. Our boiler service page sets out what a service includes, and our guide to how often a boiler should be serviced covers timing.
If something fails
Gas engineers follow the Gas Industry Unsafe Situations Procedure. An appliance classed Immediately Dangerous is disconnected, with permission, and labelled; one classed At Risk is turned off, with permission, and labelled. Either way a written warning notice is left. The landlord then has to get the fault repaired and the appliance re-checked before it is used, so it is worth booking the check with time to spare before the deadline.
Keeping the dates straight
The two-month early window makes scheduling a portfolio easier: a check done up to two months before the anniversary keeps the original date. If you use that flexibility, keep each record until two further checks have been carried out, so the run of dates can be evidenced. Gas safety is separate from electrical safety, which has its own periodic inspection requirement for private rented homes in England.
When tenants don't give access
The duty is to take all reasonable steps to get the check done. If a tenant does not give access, keep a record of every attempt: the letters or messages sent, the dates offered and any appointments missed. Book the check early in the two-month window so there is time to rearrange. If you manage several properties, for example flats in converted houses or HMOs, keep one schedule with every appliance and anniversary date, and book the safety check together with the service so each property needs only one visit a year.
Checking your engineer
Only a Gas Safe registered engineer can carry out the check. Ask to see their Gas Safe ID card, check the categories of work on the back cover the appliances in your property, and confirm the registration on the Gas Safe Register. Our registration is 541116. Our gas engineers page explains what registration covers, and you can book a landlord check by calling 0151 440 2000.
Common questions
How often does a landlord need a gas safety certificate?
Every 12 months. Since 2018 the check can be done up to two months before the anniversary date without losing that date.
Is a CP12 the same as a boiler service?
No. The CP12, or landlord gas safety record, confirms appliances are safe at the time of the check. A service cleans and adjusts the boiler and keeps the manufacturer's guarantee valid. Most landlords book both together.
How long must a landlord keep gas safety records?
At least two years. If you use the two-month early window, keep each record until two further checks have been carried out.
Do tenants need carbon monoxide alarms?
In England, since 1 October 2022, rented homes must have a carbon monoxide alarm in every room used as living accommodation that contains a fixed combustion appliance, such as a boiler, gas fire or log burner. Gas cookers are excepted.
Updated 15 October 2026
