What is a Gas Safety Certificate?

CP12 — the landlord's annual gas obligation

A Gas Safety Certificate — officially called a Gas Safety Record, informally known as a CP12 — is a formal inspection of all gas appliances, pipework, flues and ventilation within a rental property. It can only be carried out by an engineer registered with the Gas Safe Register, the UK's official gas safety regulator.

The certificate documents the condition of every gas appliance, classifies any faults by severity (see outcome codes below), and confirms whether each appliance is safe to use. A landlord's copy and a tenant's copy must both be retained.

Is a Gas Safety Certificate a legal requirement?

Yes — and it is one of the strictest compliance obligations a landlord faces. Under the Gas Safety (Installation and Use) Regulations 1998, all private landlords must:

Arrange a Gas Safety inspection every 12 months without exception
Use only a Gas Safe registered engineer — no exceptions
Provide tenants with a copy of the certificate within 28 days
Give new tenants a copy before they move in
Retain records for a minimum of 2 years

Failure to comply is a criminal offence. Penalties include unlimited fines, up to 6 months imprisonment, and invalidation of landlord insurance.

What does the Gas Safety inspection cover?

Gas boiler — operation, heat exchanger condition, flue integrity
Gas hob / cooker — burner operation, ignition, seals
Gas fire / wall heater — combustion, ventilation clearances
Flues and chimneys — spillage test, condition, draw
Pipework and connections — pressure test, joint integrity, no leaks
Ventilation — adequate air supply for all appliances
Gas meter and emergency control valve — accessible and functional
Carbon monoxide risk assessment — for all combustion appliances

How long does it take?

A typical inspection covers 1–3 appliances and takes approximately 45–90 minutes. Properties with multiple gas appliances, older boilers or complex flue systems may take longer. Our engineer will advise on arrival.

Gas Safety Outcome Codes

Understanding your CP12 result — what each classification means

After inspecting each appliance, your Gas Safe engineer will classify its condition using one of four official Gas Safe Register outcome codes. Here is what each means and what action is required.

✓ Pass — Safe

No action required

The appliance is operating correctly within Gas Safe standards. The CP12 is issued and is valid for 12 months from the inspection date.

NCS — Not to Current Standards

Advisory notice issued

Does not meet current standards but is not dangerous. Can remain in use. An advisory notice is issued and upgrade recommended at next service or replacement.

AR — At Risk

Action required within 28 days

A defect exists that could become dangerous. A Warning Notice is issued. The appliance may remain in use but must be repaired within 28 days by a Gas Safe engineer.

ID — Immediately Dangerous

Turned off on the spot — do not use

Poses immediate risk to life — gas leak, CO risk or faulty flue. Disconnected immediately. Must not be used until repaired and cleared by a Gas Safe engineer. Warning Notice left with occupier.

What's Included

Everything in your Gas Safety Certificate service

The Inspection

NICEIC approved engineer
Full fixed-wiring inspection
All circuits tested
Consumer unit assessment
Earthing & bonding check
RCD function tests

The Certificate

Official CP12 Gas Safety Record
Digital delivery within hours
PDF — for landlord & tenant
Gas Safe Register verified
Accepted by councils & councils
12-month validity

Support

Explanation of any findings
Written remediation quote if needed
Renewal reminder (5 years)
Portal storage included
Instant customer support
No hidden extras

FAQ

Gas Safety Certificate questions answered

Every 12 months. Gas Safety Certificates are annual — unlike EICRs (5 years) or fire alarm checks. You must renew before the current certificate expires, and give tenants a copy within 28 days of the new certificate being issued.

Yes — the CP12 covers all gas appliances in the property, including the boiler, gas hob, gas oven, gas fire, and any other gas-fuelled equipment. The engineer will check each one individually and document the results.

No. If your property has no gas supply and no gas appliances, a Gas Safety Certificate is not required. However, you still need a valid EICR for the electrical installation and a fire alarm check.

Yes, tenants can initially refuse, but you must be able to demonstrate you have taken all reasonable steps to comply. This means you should serve formal written notice. If they still refuse, document everything. You will not be penalised if you can show you tried. We can advise on how to handle this situation.

Typically within 4 hours of the inspection completing. The CP12 certificate is sent digitally to the email address you provide, and is also stored in your landlord portal for easy access.

Gas Safety Certificates for London Landlords

Gas Safety Certificate — London