Gas safety certificate (CP12): landlord guide 2026

Every gas appliance and flue in a rented home needs a safety check by a Gas Safe registered engineer at least every 12 months. Existing tenants get a copy of the record within 28 days of each check, and new tenants before they move in. A check done up to two months early keeps the same renewal date.

What is a CP12?

CP12 is the common name and reference for the Landlord Gas Safety Record, also known as a Gas Safety Certificate. It proves all gas appliances, fittings, and flues in your rental property have been inspected and are safe to use.

The certificate must be issued by a Gas Safe registered engineer. Only engineers on the Gas Safe Register are legally allowed to work on gas appliances and issue certificates. Check an engineer's credentials at gassaferegister.co.uk before letting them work on your property. For a detailed guide, see our Gas Safety Certificate resource guide.

The certificate includes details of each appliance checked, the results of safety tests, any defects found, and remedial action taken or required. If the engineer finds a dangerous appliance, they must disconnect it immediately and note this on the certificate.

The legal requirement

Under the Gas Safety (Installation and Use) Regulations 1998, every landlord must ensure gas appliances, fittings, and flues are maintained in a safe condition. An annual safety check by a Gas Safe registered engineer is required for each appliance and flue.

This applies to all residential tenancies where you provide gas appliances. It doesn't matter if it's a private tenancy, a company let, or a holiday rental. If you're renting out property with gas appliances, you need an annual gas safety check.

The only exception is if tenants own the gas appliances themselves (for example, they brought their own cooker). But if you supply any gas appliances, heating systems, or there are gas installations in the property, the requirement applies.

Annual inspection timing

The gas safety check must be carried out every 12 months. However, you can carry it out up to two months before the current certificate expires while maintaining the anniversary date.

For example, if your current certificate expires on 15 March 2026, you can have the inspection done anytime from 15 January 2026 onwards. If completed on 1 February, the new certificate will still be dated to expire on 15 March 2027.

This two-month window gives you flexibility for scheduling while ensuring you never miss the deadline. Many landlords book their annual inspection a month or two early to avoid last-minute problems.

What the engineer checks

During a gas safety inspection, the engineer will examine all gas appliances including boilers, cookers, fires, and water heaters. They check flues and chimneys to ensure combustion gases can escape safely, gas pipework for leaks or damage, ventilation in rooms with gas appliances, and the operation and safety features of each appliance. They also conduct combustion performance tests to ensure appliances are burning gas correctly.

The engineer will issue a pass if everything is safe, or identify any defects. Defects are classified as “At Risk” (AR) or “Immediately Dangerous” (ID). An ID defect means the appliance poses immediate danger and must be disconnected. An AR defect means the appliance could become dangerous and should not be used until repaired.

If serious defects are found, the engineer must inform you and may inform the Health and Safety Executive. You're responsible for fixing defects before the appliance can be used again.

The 28-day rule for existing tenants

This is where many landlords slip up. You must provide a copy of the gas safety certificate to existing tenants within 28 days of the inspection date shown on the certificate. The 28 days start on that date, even if the engineer sends you the certificate later or you won't see the tenant for a while.

For new tenancies, you must provide the certificate before the tenant moves in. Most landlords include it with the initial document pack at the start of the tenancy.

Failure to provide the certificate within these timeframes is a criminal offence. While prosecutions are rare, the requirement is clear, and in disputes or at tribunal, late provision weakens your position.

Just as important, you must be able to prove you provided it, so keep proof of document delivery for every copy you give out.

Record-keeping requirements

You must keep copies of all gas safety certificates for at least two years. This means when you get your 2026 certificate, you should still have your 2024 certificate on file.

In practice, keeping records longer is wise. Disputes can arise years after a tenancy ends. If a former tenant claims you never provided gas safety certificates during their tenancy, you need to be able to produce them.

Beyond the certificates themselves, keep records of when you provided them to tenants. Timestamped evidence showing the tenant received or viewed the certificate is much stronger than just having a copy of the certificate on file.

See our guide on landlord record-keeping requirements for how long to keep various documents.

Proving delivery to tenants

As well as holding a valid gas safety certificate, you need evidence that the tenant received it. That evidence matters in disputes, council investigations, and tribunal proceedings.

Poor methods: Saying “I emailed it” without proof. Claiming “I left it on the kitchen counter”. Relying on memory of handing it over in person.

Better methods: Email with read receipts (though these can be declined). Recorded delivery post (proves delivery to the address but can't show the tenant read it). Signed acknowledgement from the tenant listing specific documents received.

Best methods: Digital platforms that track when the tenant viewed the document, creating a timestamped audit trail. These systems log that you sent it and also that the tenant opened it, on what date, and at what time.

When a dispute arises, being able to produce a record showing “Gas Safety Certificate viewed by tenant on 18 March 2026 at 14:32” is far more compelling than “I definitely sent it to them”.

Multiple tenants and HMOs

If you have multiple tenants in one property, each tenant should receive a copy of the gas safety certificate. This is particularly important for HMOs (Houses in Multiple Occupation).

Some landlords provide one copy and leave it in a communal area. That is usually not enough. Each tenant must actually receive the certificate. The one exception is where there is no gas appliance in any room the tenant occupies. Then you can display a copy in a prominent place, with a note saying the tenant can ask you for their own copy.

With multiple tenants, tracking who received the certificate becomes more complex. You need individual records showing each person was provided with a copy within the 28-day window.

Our HMO compliance checklist explains how to track documents across multiple tenants in one property.

Arranging access for inspections

Your tenancy agreement should include a clause allowing you to access the property for gas safety inspections. You must give reasonable notice (typically 24 to 48 hours) and arrange a time that's convenient for the tenant where possible.

If the tenant refuses access, document your attempts to arrange the inspection. Send written requests, keep copies of correspondence, and follow up multiple times. If the tenant continues to refuse, you may need legal advice, but you cannot simply enter without permission except in genuine emergencies.

Courts generally take a dim view of tenants who unreasonably refuse access for safety inspections. But you need to demonstrate you tried to arrange access properly.

Start organising your annual inspection at least two months before the current certificate expires. This gives you time to work around the tenant's schedule and deal with any access issues.

Costs and who pays

The landlord pays for the annual gas safety inspection. This is a landlord obligation and cannot be passed to the tenant. You cannot deduct the cost from the deposit or charge the tenant separately.

Inspection costs vary by region and property size but typically range from £60 to £120 for a standard property with one or two appliances. Larger properties or those with multiple appliances will cost more.

If repairs are needed as a result of the inspection, the landlord usually pays for these too, as maintaining gas appliances in safe working order is a landlord responsibility.

Penalties for non-compliance

Failure to arrange an annual gas safety check is a criminal offence. The Health and Safety Executive (HSE) can prosecute landlords who don't comply. In the magistrates' court the maximum is 12 months in prison and an unlimited fine. In the Crown Court it is two years in prison and an unlimited fine.

In practice, prosecutions usually follow serious incidents like carbon monoxide poisoning or explosions resulting from poorly maintained gas appliances. But the risk exists, and local authorities do investigate complaints.

A missing gas safety certificate used to make a Section 21 notice invalid. Section 21 has now gone, and a gas certificate is not a condition for a Section 8 possession claim. The criminal penalties above are the risk.

Insurance is another consideration. Many landlord insurance policies make an annual gas safety certificate a condition of cover. Under the Insurance Act 2015, an insurer can't refuse a claim because you broke a term like that if you show the breach could not have increased the risk of the loss that happened. A flood claim is an example. A gas-related loss is different: a missing check could well have increased the risk. Business policies can contract out of this rule if the insurer clearly flagged it, so read your policy wording.

Common mistakes

Missing the annual deadline. Letting the certificate expire before arranging the next inspection. Set calendar reminders two months before expiry to start organising the next check.

Using non-Gas Safe engineers. Only engineers on the Gas Safe Register can issue valid certificates. Check their ID before they start work.

Failing to provide the certificate to tenants on time. Remember the 28-day rule for existing tenants and before-move-in rule for new tenancies.

Not keeping proper records. Losing copies of old certificates or having no proof you provided them to tenants.

Ignoring defects. If the engineer identifies problems, get them fixed immediately. Don't let defective appliances remain in use.

Integrating gas safety into compliance workflow

Gas safety certificates are just one part of your overall landlord compliance obligations. Integrate them into a broader compliance system that also tracks your EICR (every five years), EPC (valid for 10 years, property must meet minimum standards), HMO licence renewals if applicable, and all other required documents.

Our UK landlord compliance checklist covers all required documents and timelines.

Digital systems make this integration easier by keeping every certificate, reminder, and delivery record in one place. You can see at a glance when your gas safety certificate expires, when your EICR is due, and which tenants have received which documents.

Your gas safety routine

Gas safety certificates are mandatory for UK landlords with gas appliances. Annual inspections by Gas Safe engineers are required. Existing tenants must receive the certificate within 28 days, and new tenants before they move in. You must keep records for at least two years, and you must be able to prove you provided the certificate to tenants.

Set up a system now that handles these requirements automatically, with calendar reminders for inspections, a reliable Gas Safe engineer you book regularly, and a way of sharing certificates with tenants that creates evidence of delivery.

Most of the time, everything will run smoothly. If a dispute does arise, or you are asked to demonstrate compliance, your records are how you show you met each of these duties.

The gas safety record is one of several documents a tenancy depends on. The landlord document compliance guide lists each one, when it's due and who has to receive it.