Landlord Gas Safety Certificates, explained without the jargon
If you let a property with any gas — a boiler, a hob, a gas fire, even just the pipework — the law says you must have it checked every year by a Gas Safe registered engineer. Here is what that actually means for you, in plain English.
Last reviewed: June 2026
Check where you stand in under a minute
What is a Gas Safety Certificate (CP12)?
It is the document your engineer gives you after the annual check, confirming that the gas appliances and flues in your property are safe to use. Its official name is the Landlord Gas Safety Record, but almost everyone still calls it a CP12 — an old form number that stuck. If your paperwork says one and not the other, it is the same thing.
It is not a stamp of approval that lasts forever. It is a snapshot: on the day of the check, everything was safe. That is why it has to be renewed every year.
Do you actually need one?
If you rent out a home with gas appliances, flues or pipework that you provide as the landlord, then yes — almost certainly. This includes:
- Houses and flats let on an assured shorthold tenancy.
- Houses in Multiple Occupation (HMOs) — the same rules apply.
- Rooms let individually where there is shared gas heating or cooking.
The duty comes from the Gas Safety (Installation and Use) Regulations 1998. It applies whether or not your tenant ever switches the appliance on. The one common exception: appliances the tenant owns and brought with them are their responsibility — but the pipework and flue that serve them are still yours.
What the engineer actually checks
During the visit, a Gas Safe registered engineer will confirm that each appliance:
- is burning gas correctly and at the right pressure;
- is the right type of appliance for the room it is in;
- has a flue or chimney carrying fumes safely outside;
- has all its safety devices working; and
- has enough ventilation to run safely.
If something fails, the engineer will tell you what is wrong and how serious it is. A dangerous appliance can be disconnected on the spot — with your permission, or the tenant's — until it is fixed.
How often, and the early-renewal trick worth knowing
Once every 12 months. The detail most landlords miss: you can have the check done up to two months before the current certificate runs out, and the renewal date stays pinned to the original anniversary — you do not lose those weeks.
So if your certificate expires on 30 June, an engineer who comes in early May still gives you a new expiry of 30 June next year. The practical upside: you can book early, work around your tenant's diary, and never risk an accidental lapse waiting for an appointment.
Giving the certificate to your tenants
This is a legal duty in its own right, and an easy one to trip over:
- Existing tenants: a copy within 28 days of the check.
- New tenants: a copy before they move in.
Email is fine, as long as your tenant has agreed to receive documents that way. Keep proof that you sent it — in England, failing to give a new tenant their gas safety record can stop you from using a Section 21 notice later, even years down the line.
How much does it cost?
For a standard property with one boiler, expect roughly £60–£90 in most of the country, including Greater Manchester. More appliances — a separate gas hob, a gas fire — usually add a little per item. Prices vary by engineer, location and how many appliances you have, so it is always worth getting a couple of quotes.
Treat these as typical figures, not a fixed rate. Your engineer will give you an exact price for your property.
What happens if you do not have one
Running a let with no valid gas safety check is a criminal offence. The Health and Safety Executive (HSE) can prosecute, fines are unlimited, and the most serious cases — usually where someone has been harmed — can carry a prison sentence. Beyond the law, your insurance may not pay out on a gas-related claim if you cannot show a current certificate.
And the one that catches landlords out at the worst moment: in England you cannot serve a valid Section 21 no-fault eviction notice if you never gave your tenant their gas safety record. A missed piece of paperwork can leave you unable to regain your property when you need to.
A safety check is not a boiler service
These get muddled constantly. A safety check tells you the appliance is safe to use today — that is the legal requirement. A service is preventative care to keep it running efficiently and head off breakdowns. They are different jobs. A good engineer can do both in one visit, but only the annual safety check is required by law.
If your tenant will not let the engineer in
You are legally required to take reasonable steps to get the check done — not to break down the door. If access is a problem:
- write to your tenant explaining it is a legal safety requirement;
- offer a choice of dates, including evenings or weekends;
- keep copies of every letter, email and text.
That record of genuine attempts is exactly what protects you if a deadline slips despite your best efforts. Never force entry or threaten eviction to gain access — document, persist, and escalate calmly.
While you are at it: carbon monoxide alarms
Closely related, and often handled in the same visit. In England, since October 2022, landlords must make sure a carbon monoxide alarmis fitted in any room used as living accommodation that has a fixed combustion appliance — for example a boiler or a gas fire (gas cookers are excluded). Rules differ slightly in Scotland and Wales, so check your nation's guidance.
Keeping your records
Hold on to each gas safety record for at least two years. A simple folder — paper or a dated file on your phone — is enough. The point is to be able to show, at any time, that the property has been checked and the tenant was given their copy.
Frequently asked questions
Is it called a CP12 or a Gas Safety Certificate?
Both — they are the same thing. "CP12" is an old form number from the Corgi days; the official name today is the Landlord Gas Safety Record. Engineers, letting agents and landlords still say "CP12" out of habit, so do not worry if your engineer hands you something that says one and not the other.
How often does a landlord gas safety check need to be done?
Every 12 months. You can have the check done up to two months before the current certificate expires without losing those weeks — the new expiry date stays pinned to the original anniversary, a bit like an MOT. That means you can renew early without ever letting the cover lapse.
Do I need one if my tenant has never used the gas?
Yes. The duty is tied to the property having gas appliances, flues or pipework that you provide — not to whether the tenant uses them. If there is a gas supply and gas appliances you are responsible for, you need an annual check.
What happens if I do not have a valid certificate?
It is a criminal offence under the Gas Safety (Installation and Use) Regulations 1998. The HSE can prosecute, fines are unlimited, and serious cases can carry a prison sentence. Separately, in England you cannot serve a valid Section 21 (no-fault eviction) notice if you have not given your tenant a copy of the gas safety record.
Is a gas safety check the same as a boiler service?
No. A safety check confirms your appliances are safe to use right now. A service is preventative maintenance to keep them running well. A good engineer can do both in one visit, but the annual safety check is the legal requirement — a service is not.
What if my tenant will not let the engineer in?
You must take "reasonable steps" to get the check done, but you are not expected to force entry. Write to your tenant, offer dates, and keep copies of every attempt. That paper trail is your defence if the deadline passes despite genuine efforts. Never break in or remove a tenant to gain access.
Where this guidance comes from
We have kept this plain, but the rules behind it are real and worth reading from the source. For anything specific to your property, confirm with your Gas Safe registered engineer.
- HSE — Landlords' gas safety responsibilities
- Gas Safe Register — check an engineer is registered
- GOV.UK — your landlord's safety responsibilities
ComplyLandlord is a free informational tool, not legal advice. Always confirm your obligations with a Gas Safe registered engineer or the official sources above.