Every rented property with a gas appliance needs an annual gas safety check by a Gas Safe registered engineer, with a certificate issued to tenants. We carry out landlord gas safety checks (commonly known as a CP12) across Farnham, Guildford, Godalming, Farnborough, Fleet and Camberley, for individual landlords, letting agents and managing agents running a portfolio.
The Gas Safety (Installation and Use) Regulations 1998 place a legal duty on landlords to have every gas appliance, flue and installation pipework in a rented property checked for safety at intervals of no more than 12 months, by a Gas Safe registered engineer. This applies to any property let under a tenancy where the landlord has arranged for a gas supply, gas appliance or associated pipework to be installed or used, with limited exceptions that don't apply to the great majority of standard residential lettings.
The certificate produced from this check is generally referred to as a CP12, after the number of the form it replaced, though the regulations themselves don't use that term. Getting this wrong is not a paperwork technicality — it is a legal obligation with enforcement consequences, and it is the single most important compliance item most landlords carry.
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What the annual check covers
A statutory duty with a defined scope, not a rough visual check.
The annual landlord gas safety check follows a defined set of inspections, tenant duties and safety classifications set out in law. Here is what is involved, from what gets checked through to what happens if an appliance fails.
What's Actually Checked
A landlord gas safety check is a defined set of inspections on every gas appliance and the associated installation, carried out and recorded by the attending engineer.
Every gas appliance checked for safe operation and correct combustion
Appliance ventilation checked as adequate and unobstructed
Flue performance checked to confirm safe removal of combustion products
Physical stability and safe installation of each appliance
Gas tightness testing of the installation to check for leaks
Every appliance is classified during the check using the Gas Industry Unsafe Situations Procedure (GIUSP), and any finding is explained on the spot, not left for you to interpret from the certificate alone.
Immediately Dangerous: disconnected on the spot with the occupier's agreement
At Risk: may continue in use only with informed consent, or is turned off without it
Not to Current Standards: recorded for information, no action required at the time
Any Immediately Dangerous or At Risk finding is followed up with a clear repair quote
Landlords are expected to take all reasonable steps to arrange the annual check. Where a tenant isn't cooperating with access, a clear record of the attempts made is what demonstrates that effort.
Dated letters or messages requesting access at reasonable notice
At least two or three documented attempts, ideally with a final warning letter
Evidence that references the legal duty and the safety risk of an unchecked appliance
Engineer attendance records supplied for any visit that couldn't go ahead
The 12-month cycle allows early renewal without losing your date.
You can have the check carried out up to two months before the current certificate expires without losing your original renewal date — the new certificate's 12-month cycle then runs from the original anniversary date, not from the earlier check date. This exists so landlords aren't penalised for booking ahead of the deadline, but it doesn't extend the interval beyond 12 months from the original date, and a check carried out earlier than the two-month window resets the anniversary to that earlier date instead.
A landlord gas safety check and a boiler service cover different things and are governed by different rules. The gas safety check is a statutory requirement covering every gas appliance in the property, exists specifically to protect tenants, and must result in a certificate issued to them. A boiler service is manufacturer-recommended maintenance focused on the boiler's own performance and warranty conditions. The two are frequently confused because they can be carried out on the same visit, but a service alone does not satisfy the landlord's legal duty, and a gas safety check alone is not the depth of manufacturer-specification maintenance a service provides.
Check can be carried out up to two months early without losing the existing renewal date
The new certificate's 12-month cycle runs from the original anniversary date
A check carried out earlier than the two-month window resets the anniversary to that date
A boiler service alone does not satisfy the landlord's legal duty to certify gas safety
Reviews from real ComGas customers, shown as submitted through Google.
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Lucie Victoria
15 May 2025
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Excellent service, highly recommend
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James Mowat
30 April 2025
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Incredible service — problems fixed perfectly once again.
Lee, Paul and the team at COMGAS are fantastic. They arrived on time and got straight to work, quickly identifying the root cause of the plumbing and heating issues I was experiencing.
The problems were diagnosed swiftly, I was kept fully informed throughout, and both issues were fixed with impressive speed and precision.
Having worked in the industry for nearly 20 years, I know how rare it is to find reliable, trustworthy, and genuinely skilled professionals — let alone a team this good.
I joked about it at the time, but it’s true: I had the best shower I’ve ever had in this house after they finished the job — and I’ve lived here for 10 years!
I honestly couldn’t ask for more and can’t recommend COMGAS highly enough.
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Faz
31 March 2025
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ComGas replaced my boiler and water tank at short notice. So glad i used them. Thank you
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Laura Andrews
26 March 2025
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Lee came out to the school I work in to look at a problem with our heating, he diagnosed the issue and was able to fix it on the spot in a neat and tidy manor. Would highly recommend
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Chloe
26 March 2025
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I recently used Comgas for a gas and heating service, and I couldn't be more impressed! From start to finish, their team was professional, friendly, and highly knowledgeable. They quickly identified the issue with my heating system and explained everything in detail, offering both short- and long-term solutions.
The technician was punctual and took extra care to ensure everything was running smoothly. I really appreciated their attention to detail and how they made sure to clean up after the work was completed. My home is now warm and cozy, all thanks to their expert service. I highly recommend Comgas for anyone looking for reliable, efficient, and trustworthy gas and heating professionals!
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Bec Newey
8 July 2024
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Messaged Lee on a Sunday evening with request. Instant reply that evening and engineer came next day. Polite, professional and helpful. Thorough investigation and speedy resolution to a leak with sink in wc. Happy customer.
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P Duffy
2 April 2024
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Scott and the team have served me well over several years. Skilled craftsmen. Dependable careful and very cosy-effective. I highly recommend them.
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Cilla Trout
22 March 2024
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Definitely recommend friendly reliable service
Scott was helpful and reassuring regarding our boiler answered our concerns and explained the problem and best course of action thank you for your advice
Landlord gas safety questions
Frequently asked questions.
If a certificate has already lapsed or a tenant is not cooperating with access, contact us directly so we can prioritise attendance rather than waiting for a routine booking.
CP12 is the informal name still widely used for a landlord gas safety record — the certificate produced when a Gas Safe registered engineer completes the annual safety check required under the Gas Safety (Installation and Use) Regulations 1998. The name comes from an old form number; the regulations refer to it as the landlord's gas safety record.
How often does a landlord gas safety check need to be done?
At intervals of no more than 12 months. You can have the check carried out up to two months before the current certificate expires without losing your existing renewal date, which the new certificate will run from instead of the earlier check date.
What happens if I let a certificate lapse?
A lapsed certificate means you are letting a property without a valid gas safety record, which is a breach of your legal duty and a genuine enforcement risk, separate from the safety risk of an unchecked installation. Book the next check as soon as possible and keep a record of when it was arranged.
Do I need to give my tenant a copy of the certificate?
Yes. Existing tenants must receive a copy within 28 days of the check. New tenants must receive a copy of the current record before they move in. Both are separate duties from having the check carried out at all.
What if the tenant won't give access for the check?
Document every attempt to arrange access — dated requests, reasonable notice, and ideally a final letter referencing the legal duty. This record is what demonstrates you took all reasonable steps if the check runs late. We can supply attendance records for any visit that couldn't go ahead.
What happens if an appliance fails the check?
It's classified as Immediately Dangerous, At Risk, or Not to Current Standards. An Immediately Dangerous appliance is disconnected on the spot. An At Risk appliance may continue in use only with informed consent while repairs are arranged, or is turned off without it. Either way, you'll receive a clear explanation and a repair quote, not just a fail notice.
Is a gas safety check the same as a boiler service?
No. The gas safety check is a statutory requirement covering every gas appliance in the property, with a certificate that must go to the tenant. A boiler service is manufacturer-recommended maintenance on the boiler specifically. We can carry out both on the same visit where useful.
