Compliance Guide
Gas Safety Certificate (CP12) for Landlords — Requirements, Costs & Legal Obligations
Everything landlords need to know about CP12 gas safety certificates: legal requirements, costs (£60–£120), penalties for non-compliance, and how to find a Gas Safe engineer.
Gas Safety Quick Reference
Legal basis
Gas Safety (Installation and Use) Regulations 1998, Regulation 36. Enforced by the Health and Safety Executive (HSE). Section 21 block under Deregulation Act 2015, s.33.
Renewal cycle
Every 12 months
Who can issue
A Gas Safe registered engineer. Gas Safe Register replaced CORGI in 2009. Landlords must verify the engineer's Gas Safe ID card and check the appliance categories they are qualified to inspect at GasSafeRegister.co.uk.
Max fine
Unlimited (criminal offence)
Prison risk
Up to 6 months imprisonment and/or an unlimited fine
Section 21
Blocks if expired
1. Overview
A Gas Safety Certificate, formally known as a CP12, is a legal document confirming that all gas appliances, flues, and pipework in a rental property have been inspected and deemed safe by a Gas Safe registered engineer. The check covers boilers, gas fires, gas cookers (if landlord-supplied), and any other gas-burning appliance. Engineers test for gas leaks, check ventilation, inspect flue flow, and verify that each appliance is burning correctly and safely.
Under the Gas Safety (Installation and Use) Regulations 1998, every landlord in England, Wales, and Scotland must arrange an annual gas safety check within 12 months of the previous inspection. The certificate must be provided to existing tenants within 28 days of the check and to new tenants before they move in. Failure to comply is a criminal offence carrying an unlimited fine and up to six months in prison. Additionally, since the Deregulation Act 2015, a valid CP12 is required before a landlord can serve a Section 21 eviction notice in England.
Landlords should keep records of all gas safety checks for at least two years. If a property has no gas supply — confirmed by the meter being removed or the supply being capped at the mains — no gas safety certificate is required, but it is wise to document this. Common issues flagged during inspections include blocked flues, inadequate ventilation, faulty thermocouples, and gas leaks at pipe joints. Any defects classified as "Immediately Dangerous" or "At Risk" must be addressed before the engineer can issue the certificate.
2. Cost
A Gas Safety typically costs between £60 and £120. Price varies by number of appliances. A single boiler check is typically £60–£80; properties with multiple gas appliances (boiler, hob, fire) cost £90–£120. London and the South East tend to be at the higher end.
3. Regional Variations
England
Annual CP12 is mandatory under the 1998 Regulations. Since October 2015, a valid gas safety record is required before a Section 21 notice can be served. Local authorities can issue improvement notices and prosecute non-compliant landlords.
Wales
The same Gas Safety Regulations apply as in England. However, under the Renting Homes (Wales) Act 2016, landlords issuing a Section 173 notice (the Welsh equivalent of Section 21) must also demonstrate gas safety compliance. Rent Smart Wales registration requires landlords to confirm they meet gas safety obligations.
Scotland
Gas safety requirements are identical under the 1998 Regulations. However, Scotland's Private Housing (Tenancies) (Scotland) Act 2016 replaced assured shorthold tenancies with Private Residential Tenancies, removing Section 21 entirely. The Scottish Housing Regulator expects gas safety compliance, and the First-tier Tribunal can impose sanctions for non-compliance.
Northern Ireland
The Gas Safety (Installation and Use) Regulations (Northern Ireland) 2004 apply separately. The requirements mirror GB law, but enforcement is handled by the Health and Safety Executive for Northern Ireland (HSENI). Northern Ireland does not have a Section 21 equivalent block for gas safety, but criminal penalties still apply.
4. Gas Safety by Location
Requirements and costs vary by local authority. Select your area for council-specific guidance.
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Start tracking your Gas SafetyFrequently Asked Questions
What happens if my gas safety certificate expires?
You are committing a criminal offence from the day after expiry. The HSE or your local authority can prosecute, resulting in an unlimited fine and up to 6 months in prison. In England, you also lose the ability to serve a Section 21 notice until a valid certificate is in place. Arrange your renewal 10–12 months after the last check to avoid gaps — if done in the final month of validity, the new certificate runs from the original expiry date, so you do not lose any time.
Do I need a gas safety certificate if the property has no gas supply?
No, but you should obtain written confirmation that the gas supply has been permanently disconnected or capped at the meter. A letter from the gas network operator or a Gas Safe engineer confirming no gas supply exists is sufficient. Keep this on file in case your local authority or tenants query it.
Can I do the gas safety check myself?
No. The inspection and certification must be carried out by a Gas Safe registered engineer. Even if you are a qualified gas engineer, you must be on the Gas Safe Register and hold the correct appliance categories. Self-certification without registration is illegal.
Is a boiler service the same as a gas safety check?
No. A boiler service is a maintenance procedure — cleaning components, checking efficiency, and replacing worn parts. A gas safety check (CP12) is a safety inspection required by law. Many engineers offer a combined service and CP12 for a reduced rate (typically £100–£150), which is good practice but they are separate obligations.
What if my tenant refuses access for the gas safety check?
Document every attempt to arrange access in writing (letter, email, or text). Make at least three attempts with reasonable notice (24–48 hours). If the tenant still refuses, seek legal advice — you may need to apply for a court injunction. Keep all correspondence as evidence that you took reasonable steps, which can be a defence if prosecuted.