What Is a CP12 Certificate? A Landlord's Guide

A CP12 is the informal name for the Landlord Gas Safety Record (LGSR) — the legally required annual check confirming every gas appliance, pipework, and flue in a rental property is safe. If you’re a landlord letting a property with a gas boiler, hob, or fire, you need one every year, full stop.

Where the name “CP12” comes from

CP12 was the original form number used to record a gas safety inspection. The paperwork has been updated since, and the correct current term is Landlord Gas Safety Record (LGSR), but “CP12” has stuck as the everyday shorthand — you’ll hear both used interchangeably by landlords, agents, and engineers.

What the inspection actually covers

A proper gas safety check includes:

• Every gas appliance in the property (boiler, hob, gas fire) — checked for safe operation
• Gas pipework and fittings — checked for leaks and correct installation
• Flues and ventilation — checked to ensure combustion gases escape safely
• Safety devices and burner pressure — tested to confirm they work correctly

If an appliance fails, the engineer will explain what’s needed to fix it — sometimes it’s a simple part, sometimes it means an appliance needs replacing before a certificate can be issued.

Why it’s a legal requirement, not just good practice

Under the Gas Safety (Installation and Use) Regulations 1998, every landlord letting a property with gas appliances must:

1. Have every gas appliance and flue checked annually by a Gas Safe registered engineer
2. Keep a record of each check for at least 2 years
3. Give a copy of the current certificate to existing tenants within 28 days of the check
4. Give a copy to new tenants before they move in

Failing to comply can mean unlimited fines and up to 6 months in prison — this isn’t a paperwork technicality, it’s taken seriously because gas safety failures can be fatal.

How often it needs renewing

Every 12 months, without exception — see our full guide on how often landlords need gas safety checks for the exact timing rules if you’re trying to align it with a tenancy renewal or previous inspection date.

What happens if an appliance fails the check

If an appliance is found to be unsafe, the engineer will classify it accordingly — sometimes it can be repaired on the spot, sometimes it needs a part, and in more serious cases (an “immediately dangerous” classification) the gas supply to that appliance is capped off there and then, for safety, until it’s fixed. This is exactly why it’s worth booking your annual check with enough lead time before a certificate expiry, rather than at the last possible moment — if something does need fixing, you want time to sort it without breaching the deadline.

Keeping records properly

You’re required to keep gas safety records for at least 2 years, and to be able to produce the current certificate on request — from tenants, letting agents, or in the event of an inspection. Keeping a simple digital copy (we always email ours) alongside any paper copy means you’re never caught out searching for a document at short notice.

Getting a CP12 in Norwich

We carry out Gas Safety inspections for landlords across Norwich, Wymondham, Dereham, and Attleborough, and in most cases issue the certificate the same day by email. If your current certificate is due for renewal, or you’re not sure when your last one was carried out, get in touch and we’ll sort it.