Gas Safety Certificate for Landlords: Requirements & Costs

A gas safety certificate — formally known as a CP12 or Landlord Gas Safety Record — is one of the most critical legal documents for any UK landlord. If your rental property has any gas appliances, pipework, or flues, you are legally required to have them inspected annually by a Gas Safe registered engineer.

The consequences of non-compliance are severe: fines of up to £6,000, imprisonment for up to six months, and potential manslaughter charges if a tenant is harmed by a faulty gas appliance. Beyond the legal penalties, carbon monoxide poisoning from defective appliances kills around 30 people in the UK each year.

This guide explains everything you need to know about gas safety certificates for landlords, including what is inspected, who can carry out the check, what happens if an appliance fails, and how Latch helps you track renewal dates across your portfolio.

What Is a Gas Safety Certificate (CP12)?

A CP12 is the official record of a gas safety check on a rental property. The name CP12 comes from the original form number used by CORGI (the predecessor to Gas Safe Register). Today, the document is formally called a Landlord Gas Safety Record, but most people still refer to it as a CP12.

The certificate confirms that all gas appliances, fittings, and flues in the property have been inspected and are safe to use — or, if not, that defective appliances have been identified and condemned.

What Does the Law Require?

Under the Gas Safety (Installation and Use) Regulations 1998, every landlord must:

• Have all gas appliances, fittings, and flues in their rental properties checked for safety every 12 months
• Use a Gas Safe registered engineer to carry out the inspection
• Provide a copy of the gas safety record to existing tenants within 28 days of the check
• Provide a copy of the most recent gas safety record to new tenants before they move in
• Keep a record of each safety check for at least 2 years

What Is Inspected During a Gas Safety Check?

A Gas Safe registered engineer will inspect the following during a gas safety check:

• Gas boilers: Checking for correct operation, flue integrity, ventilation, gas pressure, and safety controls
• Gas fires: Inspecting flames, flue operation, ventilation, and safety shut-off mechanisms
• Gas cookers and hobs: Checking gas tightness, flame failure devices, and stability
• Gas water heaters: Testing operation, flue integrity, and ventilation requirements
• Pipework: Inspecting visible gas pipework for leaks, corrosion, and damage
• Flues and chimneys: Checking that combustion products are safely removed from the property
• Ventilation: Ensuring adequate ventilation for all gas appliances

The engineer will perform a visual inspection, operational checks, and may use gas detection equipment to check for leaks. They will also test the flue flow to ensure combustion gases are being properly expelled.

Who Can Carry Out the Inspection?

Only an engineer registered with the Gas Safe Register can carry out a landlord gas safety check. It is a criminal offence for anyone who is not Gas Safe registered to work on gas appliances.

What Happens If an Appliance Fails?

If the Gas Safe engineer finds that an appliance is unsafe, they must classify it according to the Gas Industry Unsafe Situations Procedure:

If an appliance is classified as Immediately Dangerous, the engineer is legally obliged to make it safe, which usually means disconnecting it. You must then arrange repair or replacement before the appliance can be used again.

A failed inspection does not mean you receive no certificate. The engineer will still issue a CP12, but it will record the appliance as unsafe and note what action was taken.

Penalties for Non-Compliance

The penalties for failing to maintain a valid gas safety certificate are severe:

Local authorities and the HSE conduct routine inspections and respond to tenant complaints. If a tenant reports a gas safety concern, enforcement officers can demand to see your certificate within a matter of days.

How Much Does a Gas Safety Check Cost?

Gas safety check costs vary by region and the number of appliances in the property:

Many landlords combine the gas safety check with an annual boiler service, which can save money and reduce disruption to tenants. The gas safety check alone typically takes 20-40 minutes depending on the number of appliances.

Timing and the MOT-Style Flexibility

Gas safety certificates must be renewed every 12 months. However, there is flexibility in the timing to prevent the renewal date from creeping later each year.

If you renew the certificate within the final two months of the current certificate's validity (i.e., up to 2 months early), the new certificate's expiry date will be 12 months from the current certificate's expiry date — not 12 months from the inspection date. This is similar to how an MOT works.

Tenant Access Issues

If a tenant refuses to allow access for the gas safety check, you must be able to demonstrate that you took reasonable steps to arrange the inspection. Best practice:

1. Write to the tenant at least 14 days in advance requesting access, giving at least 24 hours' notice of the proposed appointment
2. If the first appointment is refused or missed, write again offering alternative dates and times
3. Send a final written warning explaining the legal requirement and the consequences of continued refusal
4. Keep copies of all correspondence as evidence
5. If access is still refused, seek legal advice — you may need to apply for a court order

Documenting your attempts to arrange access is critical. If you can demonstrate that you took all reasonable steps, you may have a defence against prosecution — but this is not guaranteed.

Properties Without Gas

If your rental property has no gas supply and no gas appliances, you do not need a gas safety certificate. However, it is good practice to obtain written confirmation of this (for example, from a Gas Safe engineer or by confirming the property has an electric-only supply).

Be aware that some properties may have a gas supply to the building even if the individual flat uses only electric heating. In blocks of flats, check whether communal boilers or shared gas supplies affect your obligations.

How Latch Tracks Gas Safety Renewals

Latch makes gas safety compliance effortless across your portfolio: