Gas Safety Certificate Explained: Landlord and Homeowner Guide
A gas safety certificate is a record showing that gas appliances and flues have been checked by a qualified Gas Safe registered engineer.
The document is commonly called a CP12, although the formal term is usually Landlord Gas Safety Record or Gas Safety Record.
For landlords, this is a legal requirement. For homeowners, it is not normally a legal requirement, but regular gas safety checks and boiler servicing remain important.
This guide explains what a gas safety certificate covers, who needs one, what the engineer checks and how to keep the correct records.
What is a gas safety certificate?
A gas safety certificate records the result of a gas safety check.
During the check, a Gas Safe registered engineer examines the gas appliances, pipework and flues provided at a rental property. The engineer records whether the items are safe to use and notes any defects or remedial work.
A gas safety record should include:
- The property address.
- The landlord’s or letting agent’s name and address.
- The date of the check.
- A description and location of each appliance and flue checked.
- The engineer’s name, registration number and signature.
- Any safety-related defects identified.
- Any remedial action taken.
- Confirmation that the required safety checks were completed.
There is no single compulsory CP12 form. The record must contain the required information and must be completed by a Gas Safe registered engineer.
See the HSE guidance on gas safety check records.
Who legally needs a landlord gas safety certificate?
Landlords
A landlord must arrange an annual gas safety check if gas appliances, pipework or flues are provided for tenants to use.
This includes many types of rented property, such as:
- Houses and flats.
- Houses in multiple occupation.
- Furnished and unfurnished rental properties.
- Property managed by a letting agent.
- Short-term or holiday accommodation, subject to specific requirements.
The landlord remains responsible even when a managing agent arranges the appointment. Responsibility should be clearly allocated, but the legal duty must still be met.
The landlord must:
- Use a Gas Safe registered engineer.
- Check all relevant gas appliances and flues.
- Arrange the check at least every 12 months.
- Provide the record to tenants within the required timescale.
- Keep the required records.
- Take action if a defect or unsafe appliance is identified.
Homeowners
An owner-occupier does not normally need a CP12 by law.
A homeowner may still arrange an annual gas safety check and boiler service as good safety practice. This can help identify gas leaks, ventilation problems, flue issues and appliance faults.
Homeowners should also keep boiler service records, installation documents and any repair paperwork.
How often is a gas safety check required?
For rental properties, gas appliances and flues must be checked at intervals of no more than 12 months.
A landlord can arrange the next check during the two months before the due date without changing the original annual deadline. For example, if a check is due on 30 November, it may be completed from 30 September. The next annual deadline remains linked to 30 November.
This flexibility can help landlords arrange appointments before a tenancy or before a busy period.
A simple process is:
- Check the date of the previous record.
- Identify the next deadline.
- Book the engineer during the permitted period.
- Receive and review the completed record.
- Send the record to the tenant.
- Store the record securely.
Do not rely only on a boiler service reminder. A boiler service and a legal gas safety check are separate tasks.
What does a gas engineer check?
The exact checks depend on the appliances and installation. A gas engineer will normally consider the following areas.
Gas appliances
The engineer may check boilers, gas fires, cookers, hobs and other appliances connected to the gas supply.
The appliance should be operating correctly and without creating an unsafe condition.
Flues
Flues remove combustion products from the property. The engineer checks whether the flue is suitable, correctly connected and operating as required.
A flue problem can create a carbon monoxide risk.
Gas tightness
The engineer checks the installation for gas tightness. This helps identify possible leaks in the pipework or connections.
Ventilation
Some appliances require adequate ventilation. The engineer may check that vents are present, suitable and unobstructed.
Vents should not be covered or blocked.
Safety devices and combustion
Where appropriate, the engineer checks safety devices and appliance operation. Combustion testing may also be carried out using suitable equipment.
The engineer may need access to appliances, flues, cupboards, meter areas and ventilation points. Restricted access can prevent the check from being completed.
What happens if a defect is found?
A gas safety certificate does not always mean that every appliance has passed without comment.
If a defect is found, the engineer should record it and explain what action is required. The record should be issued after the required checks are completed. It should not be delayed until every repair has been completed.
Possible outcomes include:
- The appliance remains in use with an advisory note.
- Repair or remedial work is recommended.
- The appliance is classified as unsafe or at risk.
- The appliance is disconnected or isolated.
- Further investigation is required.
If an appliance is unsafe, it must not be used until the problem has been corrected. The landlord should arrange suitable remedial work promptly and keep records of the action taken.
Do not reconnect an appliance that has been isolated by an engineer unless it has been properly repaired and confirmed safe by a qualified person.
A landlord should keep:
- The original gas safety record.
- The defect details.
- Repair invoices or job reports.
- Any replacement appliance information.
- Confirmation that the appliance was returned to safe operation.
Gas safety check or boiler service?
These services are related but not the same.
Gas safety check
A gas safety check is a safety inspection. For landlords, it is the legally required annual check and must be recorded.
The focus is on whether the gas appliances and flues are safe to use at the time of inspection.
Boiler service
A boiler service is a maintenance appointment. It usually includes cleaning, inspection, operational testing and checks against the manufacturer’s instructions.
A service can help maintain performance, reliability and efficiency. It may also be required under a manufacturer’s warranty or service agreement.
A boiler service does not automatically replace a landlord gas safety certificate.
Landlords often arrange both appointments at the same visit. If this is done, the paperwork should clearly show:
- That the gas safety check was completed.
- Which appliances and flues were checked.
- That a boiler service was completed separately.
- Any defects or recommendations.
- Any remedial action taken.
How to book and prepare
Use a Gas Safe registered engineer for a landlord gas safety certificate or boiler service.
The Gas Safe Register provides tools to find and check registered businesses and engineers. You can also check the engineer’s identification card and confirm that the engineer is qualified for the appliance and work required.
Before booking, provide:
- The property address.
- The type and number of gas appliances.
- The date of the previous gas safety check.
- The required service, check or both.
- Details of any known faults.
- Access arrangements for the property.
Before the appointment:
- Make sure the engineer can access every gas appliance.
- Clear cupboards around the boiler.
- Keep the meter accessible.
- Check that tenants know when access is required.
- Do not cover ventilation openings.
- Have previous records available.
- Note any unusual smells, noises or appliance behaviour.
Keeping gas safety records
Landlords must provide an existing tenant with a copy of the gas safety record within 28 days of the check.
A prospective tenant should receive a copy before moving into the property.
Electronic records may be used if they are secure, can be reproduced in hard copy and identify the engineer. A tenant must receive a paper copy if requested.
Records must generally be kept for at least two years. Where the early-check flexibility is used, the record may need to be kept until two further checks have been completed.
A practical storage system can include:
- A property folder.
- The latest gas safety record.
- Previous records.
- Boiler service reports.
- Repair and replacement documents.
- Tenant communication.
- Follow-up work and invoices.
Plumbex UK Ltd gas safety services
Plumbex UK Ltd is currently launching.
As the website develops, information about available services will be added. This will include gas safety certificates, boiler servicing and gas engineer services, alongside other plumbing, heating and building services.
For future updates, service information and booking details, visit the Plumbex UK Ltd website.
Frequently asked questions
Is a CP12 the same as a gas safety certificate?
CP12 is a commonly used industry term. The formal document is generally called a Gas Safety Record or Landlord Gas Safety Record.
Do homeowners need a gas safety certificate?
Owner-occupiers do not normally need a CP12 by law. Annual gas safety checks and boiler servicing are still recommended.
Can a boiler service replace a landlord gas safety check?
No. A boiler service and a landlord gas safety check are separate services. Both may be completed during one visit, but both parts should be clearly recorded.
Can any plumber issue a gas safety certificate?
No. The check must be completed by a Gas Safe registered engineer who is qualified for the relevant appliance and type of work.
How long should a landlord keep the certificate?
Gas safety records must generally be kept for at least two years. Additional retention may be required when the early-check flexibility is used.
What should I do if I smell gas?
Do not use switches or naked flames. Turn off the gas supply if it is safe to do so, leave the property and contact the gas emergency service. Arrange inspection and repair by a qualified Gas Safe registered engineer.