Smoke alarm rules for landlords: the CO alarm gap
Most landlords know they need smoke alarms. Fewer know the carbon monoxide rule was widened, or that a council can fine £5,000 for missing either.
Last reviewed 20 July 2026 · England
Smoke alarm rules for landlords in England sound simple: fit one, done. The rule that actually catches landlords out is the carbon monoxide alarm, and specifically which rooms need one. It changed, and the folder in the sideboard rarely got the memo.
Smoke and CO alarms sit alongside gas, electrical and energy certificates as one of six certificates a landlord in England needs to track. Unlike a CP12 or an EICR, there’s no single expiry date to diarise, which is exactly why it’s easy to assume the job was done once and forget it.
What the property actually needs
The requirement is per storey, not per property. A landlord with a three-storey terraced house needs at least one smoke alarm on each of the three storeys used as living accommodation, not one alarm covering the whole building.
The carbon monoxide rule is the one most self-managing landlords get wrong. It used to apply only to rooms with a solid fuel appliance, an open fire or a wood burner. It was widened to cover any room with a fixed combustion appliance, which brings gas boilers and gas fires into scope. A landlord who fitted a CO alarm by the log burner years ago and stopped there is very likely missing one by the boiler.
| Where | What’s required |
|---|---|
| Every storey used as living accommodation | At least one smoke alarm |
| Any room with a fixed combustion appliance | A carbon monoxide alarm |
| Rooms with a gas cooker only | No CO alarm required |
| Start of every new tenancy | Landlord must test alarms are working |
The myth about who tests them
Landlords often assume that once alarms are fitted, the job belongs to the tenant. Day to day, that’s roughly right: tenants are expected to test alarms and report faults. What stays with the landlord is checking every alarm is in working order at the start of each new tenancy, and acting promptly once a fault is reported. A tenant flags a dead alarm, the landlord does nothing, and that’s the gap a council penalty follows.
The £5,000 figure
Local councils in England can issue civil penalties of up to £5,000 for breaching the smoke and carbon monoxide alarm regulations. As with gas and electrical penalties, the fine usually follows a complaint or an inspection rather than a routine check, which means a gap can sit unnoticed for months before it’s found.
What to do now
- Walk the property storey by storey and check there’s a working smoke alarm on each one used as living accommodation.
- Check every room with a boiler, gas fire or any fixed combustion appliance for a carbon monoxide alarm, not just rooms with a solid fuel fire.
- Test every alarm before a new tenancy starts, and keep a record of the date you did it. CertSorted holds that record alongside your gas, electrical and energy certificates on one screen, so it’s evidence rather than a memory.