Gas Safe Register explained — what Welsh homeowners need to know

What is the Gas Safe Register?

The Gas Safe Register is the official UK register of gas engineers legally authorised to work on gas appliances. It replaced CORGI registration in 2009 and is mandatory — no one can legally carry out gas work in Wales (or the rest of Great Britain) without Gas Safe registration.

Gas Safe is not a trade association you choose to join — it's a legal requirement enforced by the Health and Safety Executive (HSE). Gas Safe registered engineers have been assessed for competency and must requalify regularly to maintain registration.

How to check a Gas Safe engineer

Every registered engineer carries a Gas Safe ID card. On the card:

Photo and name — verify it matches the person
Registration number — check this on gassaferegister.co.uk or call 0800 408 5500
Licence type — this lists which gas appliances and work types the engineer is qualified for (e.g., domestic natural gas, LPG, commercial catering, etc.)

Critical point: Registration is individual, not company-wide. If a company employs three engineers, all three must have individual Gas Safe cards for the specific work they perform. A company being "Gas Safe registered" doesn't automatically mean every engineer they send is qualified for your specific job.

What work requires Gas Safe registration?

Any work on gas fittings, appliances, flues, and associated controls requires a Gas Safe registered engineer. This includes:

Gas boiler installation, service, and repair
Gas fire installation and service
Gas cooker installation
Flue installation, extension, and repair
Gas pipework installation and testing
Gas meter works (contact your supplier, not an independent engineer, for meter work)
LPG appliances

Work on gas appliances by an unregistered person is illegal, invalidates your home insurance, voids appliance warranties, and creates serious carbon monoxide risk.

Landlord obligations in Wales

Welsh landlords have specific legal obligations under the Gas Safety (Installation and Use) Regulations 1998 and Welsh housing law:

Annual gas safety check by a Gas Safe registered engineer for all properties with gas appliances
Gas Safety Certificate (CP12) must be issued after each check
Records kept for 2 years
Certificate must be provided to tenants within 28 days of the check (or before a new tenant moves in)

Failure to comply can result in fines, prosecution, and — in the event of an incident — unlimited liability. Landlord insurance policies also typically void in the absence of a valid CP12.

What to do if you suspect illegal gas work

If you discover gas work has been carried out without a registered engineer — for example, when buying a property — you should:

Do not use the appliance until it's been inspected by a Gas Safe engineer
Arrange an immediate Gas Safe inspection — the engineer will issue a safety notice if the work is unsafe
Report to the Gas Safe Register — call 0800 408 5500. They investigate illegal gas work reports
Carbon monoxide alarms — fit them on every floor with a gas appliance. They are legally required in rented properties in Wales

If you smell gas: leave the property, don't use electrical switches, and call the National Gas Emergency Service on 0800 111 999. This is a 24-hour free line.