Why Getting Your CP12 Right Matters
Regulation 36(3)(c) of the Gas Safety (Installation and Use) Regulations 1998 requires landlords to have a gas safety check carried out on every gas appliance and flue in a rented property every 12 months. The CP12 — formally the Landlord Gas Safety Record — is the legal document that proves this check happened.
A CP12 with missing or incorrect fields isn’t just sloppy. It can be challenged in court, void a landlord’s insurance, or fail a Gas Safe Register audit. If a tenant is harmed and the CP12 is incomplete, the engineer who signed it is personally exposed.
This isn’t just paperwork. It’s a legal document that protects the tenant, the landlord, and you. Getting every field right, every time, is non-negotiable.
The 5 Sections of a CP12
The CP12 is structured in five logical sections. Here’s what each one covers and which fields you need to complete:
The top of the form. Identifies the property being checked and who is legally responsible for it.
- •Full property address (including postcode)
- •Landlord or letting agent name
- •Landlord/agent address
- •Landlord contact details (phone/email)
- •Tenant name
- •Whether tenant was present at time of check
- •Record number
Proves who carried out the inspection. Every field here is checked during Gas Safe audits.
- •Full name
- •Gas Safe registration number
- •Employer or trading name
- •Company address and contact number
- •ID card number
Covers the gas supply and distribution before you get to individual appliances. The tightness test result here is the single most audited field on the entire form.
- •Gas type (natural gas or LPG)
- •ECV location and accessibility
- •Visual pipework condition
- •Gas tightness test result (pass/fail)
- •Equipotential bonding satisfactory (yes/no)
The bulk of the CP12. You fill in this section once for every gas appliance in the property. Miss a field here and the entire record can be challenged.
- •Location in property
- •Appliance type, make, model, and serial number
- •Flue type (open flue / room-sealed / flueless)
- •Flue flow test (pass/fail)
- •Spillage test (pass/fail/N / A)
- •Ventilation satisfactory / unsatisfactory
- •Operating pressure (mbar)
- •Burner pressure or gas rate (kW)
- •Safety devices operational (yes/no)
- •Visual condition of appliance
- •Appliance safe to use (yes/no)
- •Any defects and remedial action taken
Wraps up the record. Without both signatures and a clear overall result, the CP12 is incomplete.
- •CO alarm present, tested, and in-date
- •Smoke detectors present
- •Overall satisfactory (yes/no)
- •Additional observations
- •Engineer signature and date
- •Tenant/occupier signature and date
Section 4 is repeated for every gas appliance in the property. A house with a boiler, a gas hob, and a gas fire needs three separate Section 4 entries. Missing an appliance means the CP12 is incomplete.
Common Mistakes That Fail Audits
Gas Safe audits flag the same mistakes year after year. Here are the fields engineers most commonly get wrong or leave blank:
One of the most common audit failures. Even if the installation passed, the result must be explicitly recorded as "pass." A blank field is treated as "not tested."
A room-sealed boiler doesn’t need a spillage test — but you still need to write "N/A" in that field. Blank fields look like missed checks, not inapplicable ones. The assessor can’t tell the difference.
kW and ft³/hr are not interchangeable. Know which units your analyser reads and record them consistently. If the manufacturer’s data plate shows kW, convert before recording or note both values.
Section 3 asks for the location of the Emergency Control Valve. "Under the stairs" or "in the meter box outside front door" — it needs to be specific enough that someone else could find it in an emergency.
Just "Mr Smith" is not enough. The CP12 needs a contactable landlord: full name, address, and at least one phone number or email. If you’re working through a letting agent, record the agent’s details as well.
If the tenant is present, get them to sign. If they’re not, write "tenant not present" with the reason (e.g. "access via letting agent, tenant at work"). Never leave the signature line blank with no explanation.
Speed Tips: Fill It In Faster Without Cutting Corners
A thorough CP12 doesn’t have to be a slow one. These habits save time without sacrificing accuracy:
- 1.Pre-fill recurring property details if you visit the same properties yearly. Landlord name, address, and agent details rarely change — copy them forward and just verify on arrival.
- 2.Use your phone to photograph the appliance data badge. Saves writing down make, model, and serial number by hand, and you’ll have a backup if your handwriting is questioned.
- 3.Record operating pressure while the analyser is still connected, not from memory afterwards. One wrong digit changes the reading entirely.
- 4.Work through the form top-to-bottom as you work through the property. The CP12 follows the logical inspection order: supply first, then each appliance, then summary. Don’t jump around.
The Do’s and Don’ts
Do
- Fill in every field — leave nothing blank. Use N/A if a test doesn’t apply.
- Record the tightness test result first. It’s the most common field missed on audits.
- Write the full property address including postcode, not just the house number.
- Photograph the appliance data badge for accurate make, model, and serial number.
- Get the tenant to sign or clearly note ‘tenant not present’ with reason.
- Issue the certificate within 28 days or before the tenant moves in (Reg 36(6)).
- Keep your own copy for at least 2 years (Reg 36(3)).
Don’t
- Leave the tightness test field blank — even if the installation passed, it must be recorded.
- Write ‘boiler’ as the appliance type. Record the actual type: combination boiler, system boiler, back boiler, etc.
- Forget to check the flue termination externally. An internal-only check is not a full inspection.
- Use Tipp-Ex or cross out errors. If you make a mistake on paper, draw a single line through and initial. Better yet, use digital.
- Sign a CP12 for work you didn’t personally carry out. Your Gas Safe registration is on the line.
- Backdate certificates. If the check happened on the 15th, the date is the 15th — not the 1st.
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