How to check a gas safety certificate is valid
A certificate in the folder feels like the job is done. Whether it actually counts depends on four details most landlords never read past the date.
Last reviewed 13 August 2026 · England
You check a landlord’s gas safety certificate for one thing: the date. Most landlords in England stop there. A certificate that is in date but wrong in another way protects nobody, and the mistake usually surfaces at the worst possible moment, when a council or a tenant’s solicitor asks for it.
A CP12 is only as good as the engineer who signed it and the appliances they actually checked. Get either of those wrong and you can hold a certificate that looks complete and still counts as no certificate at all, the same position covered in what a gas safety certificate landlord fine costs you.
The four checks that matter
A valid gas safety certificate carries four details worth reading properly. Miss any one and the certificate is weaker evidence than it looks.
| Check | What it means |
|---|---|
| Engineer's registration number | Printed on the certificate, and must match the ID card the engineer carries |
| Appliance list | Every gas appliance in the property, checked, not just the boiler |
| Inspection date | The date the engineer was on site, not the date the certificate was typed up |
| Signature and company details | A named engineer and a real business, not a template with blanks left in |
Checking the engineer, not just the certificate
Every engineer who carries out a gas safety check in England must be on the Gas Safe Register, and must carry an ID card showing their registration number and which types of gas work they are qualified to do. Before the inspection, ask to see the card. After it, check the number printed on the certificate matches the card, and matches the engineer who was actually on site.
The Gas Safe Register runs a free public checker where you can confirm a registration number is current. It takes less time than reading the certificate itself, and it is the one step that separates a real inspection from a piece of paper.
The appliance list, read properly
A certificate that checks the boiler and lists nothing else is not covering a property with a gas hob or a gas fire. Read the appliance section against what is actually installed. A landlord who bought or inherited a property, covered in compliance certificates when you buy a rental property, is the case most likely to hold a certificate that quietly excludes an appliance nobody re-checked.
Why an invalid certificate is worse than an honest gap
A landlord with no certificate at least knows where they stand. A landlord holding an invalid one believes they are covered, keeps no reasonable-steps evidence beyond a document that will not hold up, and finds out the difference during an inspection or a dispute, not before one. The reasonable steps defence only works if what you can show actually stands up to a second look.
What to do now
- Pull out your current gas safety certificate and check the registration number against the Gas Safe Register’s public checker.
- Read the appliance list against what is actually installed in the property, not what you remember being there.
- Confirm the twelve-month date runs from the inspection, not from whenever the paperwork arrived.
- Keep the certificate somewhere you will actually check again next year. CertSorted holds it alongside every other certificate on one screen and reminds you at 90, 60, 30 and 7 days before the date runs out.
This applies to rental properties in England. Gas safety rules are set separately in Scotland, Wales and Northern Ireland.