Gas Safety Certificate (CP12): The Landlord's Guide
A CP12 is the single most time-sensitive certificate a landlord holds — it expires every year. Here is what it covers, the deadlines, and how the anniversary date really works.
Of all the certificates a landlord has to keep on file, the Gas Safety Certificate is the one that expires fastest — every twelve months, without fail. It is still universally called a CP12, though its formal name is now the Landlord Gas Safety Record. This guide explains what it covers, the deadlines you must hit, and the quirk in the renewal rules that can save you a fortnight's cover if you use it properly.
What the law requires
Under the Gas Safety (Installation and Use) Regulations 1998, a landlord must arrange for an annual gas safety check on every gas appliance and flue they provide as part of the let. The check has to be carried out by an engineer on the Gas Safe Register — the official register that replaced CORGI — and the resulting record kept and shared with tenants.
Note the wording: it covers appliances and flues the landlord provides. A tenant's own gas cooker, for example, is not the landlord's responsibility, but the installation pipework and any landlord-supplied boiler, fire, or hob is.
The 12-month cycle — and the two-month rule
The check is annual. The detail that trips people up — and that can quietly work in your favour — is the renewal window:
- You can carry out the new check up to two months before the current record expires.
- When you renew inside that window, the anniversary date stays the same. Renewing early does not shorten your next cycle.
In practice this means you should never leave a CP12 to the last day. Booking a few weeks early removes the risk of an engineer not being available before expiry, with no penalty to your renewal date. Leave it too late, however, and the property is non-compliant from the moment the record lapses.
Getting the record to your tenant
Holding a valid CP12 is only half the duty. You must also share it:
- To existing tenants within 28 days of the check being completed.
- To new tenants before they move in.
- And you must keep copies for at least two years.
Why this matters beyond the fine: gas safety is enforced by the Health and Safety Executive as a criminal matter, not a civil penalty. Breaches can lead to prosecution, unlimited fines and, in the most serious cases, imprisonment. A missing or invalid CP12 can also undermine a landlord's position in a possession claim.
CP12 and your boiler service are not the same thing
A gas safety check confirms appliances are safe at the time of inspection. It is not the same as a manufacturer's boiler service, which maintains performance and protects warranties. Many landlords sensibly have both done in the same visit — a Gas Safe engineer completes the CP12 and services the boiler at once — which is more efficient and keeps the appliance reliable between winters. See our boiler servicing page for what a full service includes.
Keeping it off your to-do list
The annual clock is the reason gas safety is the compliance task most likely to slip — especially across a portfolio where every property has its own anniversary date. Mainteniq issues CP12 certificates through Gas Safe registered engineers across London and the Home Counties, and can manage the renewal cycle for you as part of a planned maintenance contract, alongside your EICR and other obligations, so a certificate never lapses without warning. See our CP12 service for London landlords.
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