If you’re a landlord in the UK, a valid gas safety certificate isn’t optional — it’s a legal requirement. Whether you let a single flat in Croydon or manage a portfolio of rental properties across South London, the law requires you to have every gas appliance in your property inspected by a Gas Safe registered engineer every 12 months.
At DCN ServTech, we carry out hundreds of landlord gas safety inspections every year for individual landlords, letting agents, and property management companies across Croydon and South London. In this guide, we’ll explain exactly what’s required, what happens during an inspection, what it costs, and what happens if you don’t comply
What Is a Landlord Gas Safety Certificate?
A landlord gas safety certificate — officially called a Landlord Gas Safety Record, and commonly known as a CP12 — is a legal document confirming that all gas appliances, fittings, pipework, and flues in a rental property have been inspected and are safe to use.
The certificate is issued by a Gas Safe registered engineer after a thorough inspection. It records what was checked, what condition each appliance was in, and whether any faults were found.
The name “CP12” dates back to the CORGI Proforma 12, which was the standard form used before Gas Safe Register replaced CORGI as the official registration body in 2009. The term CP12 is still widely used by landlords and engineers across the industry.
What Does the Law Require?
The legal requirements come from the Gas Safety (Installation and Use) Regulations 1998, and they apply to every landlord in England, Scotland, and Wales who lets a property with gas appliances. The core obligations are:
Annual inspection. All gas appliances, fittings, pipework, and flues provided by the landlord must be checked at least once every 12 months by a Gas Safe registered engineer.
Certificate to tenants. A copy of the gas safety record must be given to existing tenants within 28 days of the inspection. New tenants must receive a copy before they move in.
Record keeping. Landlords must keep copies of gas safety records for at least two years. Best practice is to retain them for the duration of the tenancy and at least six years beyond, as this covers the limitation period for most civil claims.
Continuous compliance. There is no grace period. From the moment your certificate expires, you are in breach of the law for every day the property remains occupied without a valid record.
These rules apply regardless of how many properties you own. A landlord with one buy-to-let flat has exactly the same obligations as a landlord with fifty.
What Gets Checked During a Gas Safety Inspection?
During a CP12 inspection, our Gas Safe registered engineer will carry out a comprehensive check of every gas appliance and associated installation in the property. This typically includes:
Gas boiler — checking for correct operation, gas tightness, flue integrity, ventilation, and combustion performance. The engineer will also check the boiler’s safety devices and controls.
Gas cooker and hob — inspecting the gas supply connection, burner operation, flame picture, and ensuring the appliance is stable and properly installed.
fire — checking the gas supply, flue draught, combustion, and general condition.
pipework — performing a gas tightness test to check for leaks across the entire system.
Flues and ventilation — inspecting all flues for blockages, damage, or incorrect termination, and checking that ventilation openings are adequate and unobstructed.
If any appliance is found to be unsafe, the engineer will classify the fault. An “Immediately Dangerous” (ID) appliance will be disconnected on the spot and must not be used until repaired. An “At Risk” (AR) appliance may still operate but has a defect that could become dangerous if not addressed.
A standard gas safety inspection for a property with one boiler and one gas cooker typically takes between 30 and 60 minutes.
What Happens If You Don’t Have a Valid Certificate?
The penalties for non-compliance are serious and getting stricter:
Fines of up to £6,000 per offence. Each property without a valid certificate is a separate offence.
Criminal prosecution. In serious cases, landlords can face up to six months in prison.
Inability to regain possession. Under the Renters’ Rights Act 2025, compliance with gas safety obligations is now a prerequisite for certain grounds for possession. Without a valid certificate, courts may refuse to grant a possession order, even if you have legitimate grounds for eviction.
Insurance invalidation. Most landlord insurance policies require you to meet all legal obligations. If you don’t hold a valid gas safety certificate and an incident occurs, your insurer may refuse to pay out.
Liability for harm. If a tenant is injured or killed due to a faulty gas appliance in a property without a valid certificate, you as the landlord could face both criminal charges and civil claims for damages.
The simple truth is that a gas safety certificate costing £60–£80 per year protects you from thousands of pounds in potential fines, legal costs, and liability.
How Much Does a Landlord Gas Safety Certificate Cost?
At DCN ServTech, our pricing for landlord gas safety certificates in Croydon and South London is straightforward:
Single gas appliance (e.g., boiler only): From £60 Two gas appliances (e.g., boiler + gas cooker): From £75 Multi-property discounts: Available for landlords and agents with 3 or more properties — contact us for a quote. Combined CP12 + boiler service: Discounted rate available — save time and money by booking both together.
All prices include the inspection, the certificate, and any gas tightness testing required. If any faults are found during the inspection, we’ll provide a separate quote for repairs — and in many cases, we can carry out the repair during the same visit.
The 2-Month Early Renewal Window
Since 2018, landlords can take advantage of an early renewal window that gives you flexibility without losing time on your certificate cycle. If you book your gas safety check up to two months before your current certificate expires, the new certificate will be dated from the expiry of the previous one — not from the date of the inspection itself.
For example, if your current certificate expires on 1 August 2026, you can arrange the inspection any time from 1 June 2026 onwards. The new certificate would still be valid until 1 August 2027. This is useful because it means you can plan inspections at a convenient time without shortening your compliance period. However, this only applies if your previous two checks were completed on time. If you can’t demonstrate timely compliance for the last two years, the new certificate starts from the actual inspection date.
Tips for Landlords to Stay Compliant
Set a calendar reminder 10 weeks before expiry. This gives you time to book within the early renewal window and still have a buffer.
Use our annual reminder service. We track your certificate expiry dates and contact you when it’s time to rebook. You never miss a deadline.
Book access with tenants early. Give your tenants at least two weeks’ notice of the inspection. If they refuse access, you must show you’ve taken “reasonable steps” to comply — document every attempt in writing.
Keep certificates organised. Store digital copies of every CP12 alongside your tenancy records. You may need to produce them years later in the event of a dispute or claim.
Combine with a boiler service. An annual boiler service and CP12 inspection done together costs less than booking them separately and ensures your boiler stays in top condition.
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