If you let out a property in Doncaster, the Gas Safety Certificate is the one piece of paperwork you cannot afford to let slip. Whether you own a single terrace in Hexthorpe, a portfolio across Bessacarr and Balby, or a new buy-to-let on one of the developments out at Lakeside, the law treats you exactly the same: every gas appliance in the property must be checked once a year by a Gas Safe registered engineer, and you must be able to prove it.
Most landlords know the certificate exists. What trips people up is the detail — what document you actually need, who is legally allowed to issue it, when the clock resets, and what happens if you get it wrong. Get any of those wrong and you are not just risking a fine; you can invalidate your landlord insurance and lose the ability to evict a tenant when you need to. This guide walks through all of it, the way I explain it to landlords on the doorstep across Doncaster.
What Is a Gas Safety Certificate (CP12)?
A Gas Safety Certificate is the document a Gas Safe registered engineer gives you after carrying out the annual gas safety check on a rental property. Its proper name is the Landlord Gas Safety Record, but almost everyone still calls it a "CP12" — the old industry code for the form, which has stuck. If a letting agent, tenant or solicitor asks for your "CP12" or your "gas cert", this is the document they mean.
It records every gas appliance and flue in the property, confirms each one was inspected, and lists any defects found. It is not the same as a boiler service, and it is not the same as an Energy Performance Certificate (EPC) or an electrical (EICR) report — three different things landlords often muddle together. The CP12 is specifically about gas safety.
The Law: What Every Doncaster Landlord Must Do
Your duties come from the Gas Safety (Installation and Use) Regulations 1998. They apply to all residential lettings in England, Doncaster included. In summary, as a landlord you must:
- Have every gas appliance and flue checked once every 12 months by a Gas Safe registered engineer. This covers the boiler, gas fire, gas hob or cooker, and any other gas appliance you own and provide.
- Use a Gas Safe registered engineer — not just any tradesperson. Only an engineer on the official register, qualified for the appliance type, can carry out the check and issue the record.
- Give the existing tenant a copy of the record within 28 days of the check being completed.
- Give any new tenant a copy before they move in.
- Keep a copy of each record for at least two years.
Appliances that the tenant owns and brought with them are generally their responsibility, but anything you supply as part of the let is yours to certify. If you are unsure where the line falls in your property, it is worth asking the engineer on the day.
What Actually Gets Checked
On a typical Doncaster rental, the engineer will work through each gas appliance and check:
- That the appliance is burning correctly and the gas is combusting safely.
- That harmful gases such as carbon monoxide are being removed properly through the flue.
- That the flue or chimney is clear and routes exhaust gases safely outside.
- That ventilation to the appliance is adequate.
- That safety devices on the appliance are working.
- That the gas pressure and the tightness of the gas supply are correct.
If an appliance fails any of these, the engineer records the defect and — where there is an immediate danger — may classify it "At Risk" or "Immediately Dangerous" and, with your permission, disconnect it until it is repaired. That is the system working as intended: it is far better to find a flueing fault on a routine check than after a carbon monoxide incident.
CP12 vs Boiler Service — They Are Not the Same Thing
This is the single most common confusion I see. A Gas Safety Certificate is a safety check — it confirms the appliances are safe to use right now. A boiler service is preventative maintenance — the engineer strips down, cleans and tests the boiler to keep it running efficiently and reduce the chance of a breakdown. The safety check does not include the deeper clean and component inspection of a full service.
Many landlords sensibly book both at the same visit, which keeps the boiler reliable and the tenants warm as well as compliant. If you want to understand what a proper service involves and why it protects the manufacturer warranty, our Doncaster boiler service guide explains it in full. For the difference a regular service makes going into the colder months, see our piece on servicing your boiler before winter.
How Much Does a Gas Safety Certificate Cost in Doncaster?
Prices vary with how many appliances need checking and whether you combine the certificate with a service. As a rough guide for the Doncaster area in 2026:
Indicative Doncaster prices (2026)
Gas Safety Certificate, one appliance (boiler only): typically £60–£90
Each additional appliance (gas fire, gas cooker): usually a small added charge per appliance
Certificate combined with a full boiler service: often the most cost-effective option in one visit
These are general market ranges, not a quote. The exact price depends on your property and appliances — call us on 01302 963007 for a fixed figure.
Be cautious of anyone offering a certificate far below the going rate, or willing to issue one without seeing every appliance. A Gas Safety Record is a legal safety document — it is only worth anything if the check behind it was done properly by a registered engineer.
What Happens If You Don't Have One
Letting a property with gas appliances and no valid Gas Safety Record is a criminal offence, and the consequences are serious:
- Fines and prosecution. The Health and Safety Executive can prosecute, with substantial fines and, in the worst cases involving harm, far heavier penalties.
- Invalidated insurance. Most landlord insurance policies are void if you have not kept up gas safety compliance — so a gas-related claim could be refused.
- You cannot serve a valid Section 21 notice. In England, if you have not provided the tenant with a current Gas Safety Record, a Section 21 "no-fault" eviction notice can be ruled invalid — leaving you unable to regain possession when you need to.
The certificate is cheap. The exposure from not having one is not. Set a recurring reminder a month before each one is due so a renewal never slips past the 12-month mark.
Renewal tip: you can have the next check done up to two months before the current certificate expires without losing those weeks — the new expiry date stays exactly 12 months on from the old one. That means you can book early to fit the tenant's schedule and stay continuously compliant, with no penalty for being ahead.
How to Book a Gas Safety Certificate in Doncaster
It is a quick, straightforward visit. To make it smooth:
- Have your appliance list ready. Tell us how many gas appliances are in the property — boiler, fire, cooker — so we can quote accurately and allow the right time.
- Sort access with the tenant. We can liaise directly with your tenant to arrange a convenient time if you would rather not coordinate it yourself.
- Decide whether to add a service. If the boiler is also due its annual service, combining the two in one visit usually saves money and a second appointment. See our boiler installation and servicing page for details on our annual boiler service.
We carry out landlord gas safety checks across Doncaster and all the surrounding DN postcodes, and you receive your record promptly so you can pass it straight to your tenant or letting agent. To confirm an engineer is genuinely qualified to issue your certificate, our guide on how to spot a Gas Safe registered engineer in Doncaster is worth two minutes of your time. You can also read more about our wider Gas Safe engineer services in Doncaster.
Book Your Landlord Gas Safety Certificate
Single property or a full Doncaster portfolio — Yorkshire Green Heating will carry out your annual gas safety check, liaise with your tenants on access, and get your certificate to you fast. Gas Safe registered, fully insured, rated 9.82/10 across 600+ Checkatrade reviews.
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