A Gas Safety Certificate, commonly called a CP12, proves that the gas appliances, fittings and flues in a rented property have been inspected and are safe.
- Official name: Landlord Gas Safety Record
- Common name: CP12, after the old form reference
- Valid for: 12 months
- Applies to: every rental property with gas appliances
- Required by: the Gas Safety (Installation and Use) Regulations 1998
- Issued by: Gas Safe registered engineers only
If you let a property anywhere in West Sussex and Surrey, from Crawley and Horsham to Redhill and Reigate, the certificate is not optional. It is a legal requirement, and failing to keep a valid one can mean heavy fines, imprisonment and invalidated insurance. This guide covers what landlords and letting agents need to know, from the legal obligations to what the engineer actually checks.
Your legal obligations
Annually you must arrange the gas safety check, use a Gas Safe registered engineer, have every gas appliance and fitting you provide checked, and keep the records for at least two years.
For tenants you must provide a copy to existing tenants within 28 days of the check, provide one to new tenants before they move in, keep proof you did so, and ensure reasonable access for inspections.
If you do not: unlimited fine, up to six months imprisonment, invalidated insurance, and prosecution in the event of a death. Enforcement action can also stop you letting the property until it complies.
This is the position at the time of writing. Landlord law does change, so if you are unsure where you stand, check the current guidance or take legal advice.
What gets checked
All gas appliances you provide, including boilers, fires, cookers and hobs. Gas hot water systems, space heaters and any other gas appliance supplied with the property are included too. For each one the engineer checks:
- Operating pressure and heat input, confirming the appliance is getting the correct gas supply
- Flue flow and ventilation, confirming combustion gases escape safely
- Safety devices, including flame failure protection and safety cut-offs
- Carbon monoxide levels, since carbon monoxide cannot be seen or smelt
- Pipework condition, looking for leaks, corrosion and damage
- General visual condition for obvious defects
Pass, AR and ID
After the inspection, each appliance is given one of three results.
Pass. The appliance meets safety requirements and can continue in use.
AR, At Risk. There is a fault that could become dangerous. Not immediately dangerous, but it needs repairing promptly. Action is required, and it should not be left until the next annual check.
ID, Immediately Dangerous. The engineer must disconnect it there and then. It cannot be used until repaired by a Gas Safe engineer, and the engineer is legally obliged to report it. An ID appliance is a danger to life or property as it stands.
If an appliance fails
Repairs are quoted separately from the inspection. If something is marked AR or ID, you should get a clear explanation of what is wrong and a price to put it right, not just a mark on a form. Get AR faults booked in promptly, and do not let anyone use an ID appliance until it has been repaired.
What it costs
The price of a CP12 depends mainly on how many gas appliances the property has. A flat with only a boiler takes less time to check than a house with a boiler, a gas cooker and a gas fire.
A few things are worth knowing before you book:
- The inspection price covers the check only. Any repairs are quoted separately.
- Booking the CP12 alongside the annual boiler service is cheaper than two separate visits.
- If you have several properties, ask about a portfolio discount.
Our gas safety certificates are a fixed price per property, and the certificate is issued the same day. Letting agents and landlords with regular volume can also use our trade and landlord service.
When to book
Book at eleven months. Most engineers will do the check while the previous certificate is still valid, which keeps your annual cycle intact and removes any risk of a gap.
Two to four weeks notice is sensible, since engineers get very busy at certain points in the year, particularly summer ahead of student lets.
| When | What to do |
|---|---|
| Eleven months after the last check | Book the next one while the current certificate is still valid |
| Within 28 days of the check | Give existing tenants a copy |
| Before a new tenant moves in | Give them a copy |
| Twelve months after the last check | The certificate expires, so the new one must already be in place |
If a tenant refuses access
This is one of the most common problems landlords run into. Tenant refusal on its own is not a defence, and you remain responsible, so the aim is to be able to show you did everything you reasonably could.
- Give written notice, at least 24 hours and preferably more.
- Offer several appointment options and be flexible about timing.
- Explain that the check is a legal requirement, not a routine visit that can be put off.
- Document every attempt, keeping the letters, emails and texts.
- Follow the access procedure in your tenancy agreement.
- Take legal advice if access is still refused. You may need to apply to the court for access.
Flexibility on timing solves many of these. We work seven days a week, including Saturday and Sunday from 10am to 3pm, so it is usually possible to find a slot that suits the tenant.
Combining it with a service
Many landlords book the CP12 and the annual boiler service together. One visit means less tenant disruption, it costs less than two separate appointments, and the service is what keeps the boiler warranty valid.
It also reduces the risk of a breakdown in the middle of a tenancy, and a serviced boiler runs more efficiently, which your tenants will notice in their bills. A combined visit covers the full gas safety check on every appliance plus a complete service on the boiler, including cleaning components and setting it up to run as efficiently as it should. Our boiler servicing is from £105.
Record keeping
Keep the current certificate and the previous one, retain proof you gave copies to tenants, and store everything for at least two years. Scan or photograph them and keep them with your property records, because paper certificates get lost exactly when the local authority asks for one.
Keep them where you can produce them quickly. The HSE or the local authority can ask to see them, and digital copies also make it easy to share certificates with your letting agent.
Frequently asked
Do I need a CP12 for each property I rent out?
Yes. Every rental property with gas appliances needs its own valid certificate. For an HMO, each room with a gas appliance must be covered on the certificate.
Can I have the check done before the old certificate expires?
Yes, and you should. You can have it done up to two months early and the new certificate still runs from the original expiry date rather than the inspection date, so you lose nothing and avoid any gap.
What is the difference between a CP12 and a boiler service?
A CP12 is a legally required safety inspection covering all gas appliances. A service is maintenance on the boiler itself, cleaning and testing components, and it is what keeps the manufacturer guarantee valid. Landlords generally need both, and booking them together costs less.
What happens if a tenant refuses access?
You remain legally responsible, and tenant refusal is not a defence. Give written notice, offer flexible appointment times, explain that it is a legal requirement, and document every attempt in writing. We contact tenants directly to arrange access, which resolves most cases.
I am a tenant. Is the gas safety check my responsibility?
No. Arranging the annual check is your landlord's responsibility, not yours. You should be given a copy of the current record within 28 days of each check, or before you move in if you are a new tenant. Your part is allowing reasonable access when the check is booked.