Landlord Gas Safety Certificates — What You Need to Know

If you're a landlord in Surrey — or anywhere in England — you're legally required to have a gas safety check carried out on every gas appliance in your rental property every 12 months. The certificate you get at the end is commonly called a CP12, and it's one of the most important documents you'll hold as a landlord. No certificate means no legal compliance, and the consequences of getting it wrong are serious.

I carry out gas safety inspections for landlords and letting agents across Addlestone, Weybridge, Chertsey, Staines, Egham, and the wider Surrey area, so I see a lot of questions about what's required, what it costs, and what actually happens during the visit. This post covers all of it.

What is a CP12 gas safety certificate?

A CP12 — formally called a Landlord Gas Safety Record — is the document issued after a Gas Safe registered engineer has inspected every gas appliance, flue, and pipework installation in a rental property. It records what was checked, the results of the tests, and whether each appliance is safe to use.

The name "CP12" comes from the old CORGI registration system (Confederation of Registered Gas Installers), but it's still widely used even though Gas Safe Register replaced CORGI in 2009. Your tenants, letting agent, and local authority will all understand what you mean when you say CP12.

What does the law actually require?

The Gas Safety (Installation and Use) Regulations 1998 set out the rules. As a landlord, you must:

Have every gas appliance checked annually. This includes boilers, gas fires, gas cookers, and gas hobs. If it uses gas, it needs checking. The inspection must be carried out by a Gas Safe registered engineer — not just any plumber or heating engineer.

Keep records for at least two years. You need to retain a copy of each gas safety record for a minimum of two years. In practice, keeping them for longer is sensible — especially if a dispute or insurance claim arises.

Give a copy to your tenants. Existing tenants must receive a copy of the record within 28 days of the check. New tenants must receive a copy before they move in. If you use a letting agent, make sure they're actually passing this on — it's your responsibility even if you've delegated the admin.

Complete the check within 12 months of the previous one. There is a small flexibility window — if you arrange the check within the last two months of the 12-month period, the next due date still counts from the original anniversary. This is useful if you're trying to sync it with a tenancy renewal or your annual service schedule.

What happens during a gas safety inspection?

When I carry out a landlord gas safety check, I work through every gas appliance in the property systematically. Here's what's involved:

Visual inspection. I check each appliance for obvious signs of damage, corrosion, or poor installation. I also check that there's adequate ventilation in the room where the appliance is fitted — particularly important for older open-flue boilers and gas fires.

Flue and chimney checks. I test each flue to make sure combustion gases are being safely carried out of the property. For room-sealed boilers (the most common type in modern homes), this means checking the flue terminal outside for obstructions and correct positioning. For open-flue appliances, I carry out a spillage test to check that exhaust gases are drawing up the flue correctly.

Gas tightness test. I test the gas pipework for leaks. Even a small gas leak is a safety hazard and must be repaired before the property can pass.

Operating pressure and gas rate. I check that each appliance is receiving the correct gas pressure and burning gas at the manufacturer's specified rate. Incorrect gas pressure can cause incomplete combustion, leading to carbon monoxide production.

Safety devices. Every gas appliance has built-in safety mechanisms — flame failure devices on cooker hobs, overheat thermostats on boilers, and so on. I test these to make sure they'd shut the appliance down safely if something went wrong.

Combustion analysis. For boilers and gas fires, I use a calibrated flue gas analyser to measure the combustion gases. This is the key carbon monoxide safety check. The readings are recorded on the certificate.

What if an appliance fails?

If I find an appliance that isn't safe, I'm legally required to classify it using one of three categories:

At Risk (AR). The appliance has a fault that could become dangerous if it isn't addressed. I'll advise you to get it repaired, and the tenant is asked to agree not to use it until it's fixed. It gets recorded on the certificate as At Risk.

Immediately Dangerous (ID). The appliance is an immediate threat to life. I must disconnect it or turn off the gas supply to it before I leave the property. This isn't optional — it's a legal requirement. Common causes include cracked heat exchangers, blocked flues, and evidence of carbon monoxide spillage.

Not to Current Standards (NCS). The appliance is safe to use but doesn't meet current installation standards (which may have changed since it was originally fitted). This is recorded on the certificate but doesn't prevent the property from passing.

If an appliance is classified AR or ID, it won't pass the gas safety check until the fault is repaired and the appliance is retested. I can usually carry out the repair and retest on a follow-up visit, and in many cases the same day if parts are available.

Gas safety check vs boiler service — what's the difference?

This is a common source of confusion. A gas safety check and a boiler service are two different things, although they're often done at the same time.

The gas safety check is the legal compliance inspection — it confirms that each appliance is safe to use and produces the CP12 certificate. The boiler service is a maintenance procedure — stripping down the boiler, cleaning internal components, checking the heat exchanger, testing the expansion vessel, and so on. The service keeps the boiler running efficiently and maintains the manufacturer's warranty.

You need both. The gas safety check keeps you legal, and the service keeps the boiler in good condition and prevents breakdowns. I do both together for landlords in a single visit, which saves time and keeps costs down.

How much does a landlord gas safety certificate cost?

For a standard property with one gas boiler, a CP12 inspection in Surrey typically costs between £70 and £110 including VAT. If you add a full boiler service at the same visit, a combined price of £145 to £180 is typical. Properties with multiple gas appliances — say a boiler, a gas fire, and a gas cooker — will cost a little more because each appliance needs individual testing.

Be cautious of prices that seem too low. A proper gas safety inspection takes time — typically 30 to 45 minutes for a single boiler, longer if there are multiple appliances. If someone is offering to do it in 10 minutes for £30, they're not doing it properly, and a worthless certificate won't protect you if something goes wrong.

What are the penalties for not having one?

The Health and Safety Executive (HSE) takes landlord gas safety seriously. If you don't have a valid CP12 for your rental property, you could face:

A fine of up to £20,000 for each breach, issued by the magistrates' court. In more serious cases, the penalty can be unlimited.

Up to 6 months in prison for a summary conviction, or up to 2 years on indictment if the case is serious enough to go to Crown Court.

Invalidated insurance. If a gas-related incident occurs in your property and you don't have a valid gas safety record, your landlord insurance is almost certainly void. This applies to both buildings insurance and public liability.

Difficulty with Section 21 notices. In England, you cannot serve a valid Section 21 eviction notice if you haven't provided the tenant with a copy of the current gas safety certificate. This can cause significant delays and legal costs if you need to regain possession of your property.

Beyond the legal consequences, there's the moral one. Carbon monoxide poisoning from faulty gas appliances kills people every year. An annual gas safety check is a straightforward way to protect your tenants and yourself.

What about properties with no gas supply?

If your property has no gas supply and no gas appliances whatsoever — fully electric heating, electric cooker, electric hot water — then you don't need a CP12. However, if there's a gas meter on the property even if nothing is connected to it, it's worth getting the pipework capped and tested to confirm there are no leaks. If there's any gas installation at all, get it checked.

Tips for landlords managing multiple properties

If you manage several rental properties across Surrey, there are a few things that make life easier:

Sync your renewal dates. Using the two-month flexibility window, you can gradually align all your CP12 dates to fall in the same month. This makes it easier to keep track and means I can visit multiple properties in one trip, which can reduce the overall cost.

Build a relationship with one engineer. Using the same Gas Safe registered engineer each year means they know your properties, they know the history of each appliance, and they'll spot things that have changed since last time. It also means you have one phone number to call when something goes wrong.

Keep digital copies. A photo of the certificate on your phone is fine for day-to-day reference, but keep the originals filed properly. If a letting agent is managing the property, make sure you have your own copies too — don't rely solely on the agent.

Combine the CP12 with an annual service. Getting the gas safety check and boiler service done in a single visit saves time and money, and means the boiler gets proper maintenance attention at the same time as the legal check.

Need a landlord gas safety certificate in Surrey?

I carry out CP12 inspections for landlords and letting agents across Surrey — from Addlestone and Weybridge to Staines, Egham, Woking, and everywhere in between. I can usually book you in within a few days, and I'll liaise directly with your tenants or letting agent to arrange access.

Give me a call on 07311 811574 or get in touch to arrange your gas safety inspection. If you've got multiple properties, we can work out a schedule that keeps everything in sync and makes your life easier.