How Long Does a Gas Safety Check Take? What London Landlords Need to Know

For most rental properties in London, a gas safety inspection takes:

• **1 gas appliance (e.g. combi boiler only):** 30–45 minutes
• **2 appliances (boiler + gas hob):** 45–60 minutes
• **3–4 appliances (boiler, hob, oven, gas fire):** 60–90 minutes
• **Larger properties or complex installations:** Up to 2 hours

The most common scenario — a flat with a combi boiler and a gas hob — takes around 45–60 minutes from the engineer arriving to the tenant signing off.

Every gas appliance, flue and connection is inspected in sequence. For each appliance, the engineer:

1. Checks for gas leaks at every connection point using a gas detector 2. Tests that combustion is clean and the appliance burns efficiently 3. Inspects the flue for obstruction, deterioration and safe termination 4. Verifies safety devices (overheat cut-out, pressure relief valve) function correctly 5. Tests gas pressure at the meter and appliance 6. Checks the condition of pipework for corrosion or damage

For a boiler, this includes removing the casing to inspect the heat exchanger and burner. For a gas hob or oven, the engineer checks every burner and the ignition system.

The findings are recorded on the CP12 form and, once the inspection is complete, emailed to you as a digital certificate.

Briefly, yes — but only for a few minutes at a time. To test for leaks, the engineer will isolate individual appliances and sections of pipework. There's no extended period without gas; the interruption is typically a few seconds to a minute per appliance.

Your tenant can usually remain in the property throughout — the inspection is quiet, non-disruptive and doesn't require furniture to be moved.

At Landlord Compliance London, your Gas Safety Certificate (CP12) is emailed to you the same day the inspection is completed — typically within a few hours of the engineer leaving the property.

The certificate is a digital PDF you can forward directly to your tenant or upload to your property management system. You must provide a copy to your tenant within 28 days of the inspection, and to new tenants before they move in.

If any appliance fails the inspection, you'll receive a notification on the day with a clear explanation of the fault and a no-obligation quote for repair. The certificate for any appliances that did pass will still be issued; only failed appliances are noted as not to standard.

At Landlord Compliance London, you can book online via our contact form or call 07426 409342. We cover all 32 London boroughs and the M25 corridor, and can usually arrange an appointment within a day or two — often same-day for urgent jobs.

We also contact your tenant directly to arrange access at a time that suits them, so you don't need to coordinate the visit yourself.