Understand it · practical guide
UK carbon monoxide alarm law, explained without the legalese
In one line: England's rules since October 2022, the £5,000 penalty and how it actually triggers, and where Scotland and Wales go further.
Carbon monoxide law in the UK is a patchwork — England, Scotland and Wales each set their own minimums, and most summaries blur them together. Here is what is actually required, what happens if a landlord ignores it, and where the law is stricter than most people assume. (Northern Ireland's position is noted at the end.) This is general information, not legal advice — the live sources are the regulations themselves and GOV.UK.
England: the rules since 1 October 2022
The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, as amended in 2022, put three duties on landlords of specified tenancies. First, at least one smoke alarm on every storey of the property that has a room used as living accommodation — hallways and landings count as living accommodation, storage cupboards don't. Second, a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance — boiler, gas fire, wood burner — with one specific exception: a gas cooker alone doesn't trigger the requirement. Third, alarms must be tested on the day a new tenancy begins, and once a tenant reports an alarm faulty, the landlord must repair or replace it. CO alarms are expected to meet BS 50291; smoke alarms BS 5839-6. These duties apply to social landlords too since the 2022 amendment — previously the CO rule only covered solid-fuel appliances and private tenancies.
The £5,000 penalty — and the step before it
The fine everyone quotes has a step in front of it that most summaries skip. A council that finds a breach serves a remedial notice giving the landlord 28 days to fix it. Only if the landlord fails to comply does the council do the work itself and levy a penalty of up to £5,000 — per breach, not per portfolio. In other words: fixing a missing alarm within the notice window avoids the fine, which is exactly as it should be, but the notice itself is enforcement on the record. And no fine is the only thing at stake — the civil liability after a CO incident in a non-compliant property dwarfs any penalty.
What the law does not ask — but fire services do
The regulations are a floor, not a target. Nothing in the English rules requires an alarm in a room with only a gas cooker, yet cookers are a genuine CO source. Nothing requires a CO alarm near sleeping areas on every level, which is what US guidance and plain prudence suggest. And nothing stops a landlord from meeting the letter of the law with a three-year-old alarm whose sensor is nearing the end of its life — which is a whole subject of its own.
Scotland and Wales: stricter still
Scotland has required interlinked alarms since February 2022 — smoke alarms in circulation spaces and the room most frequently used as a living room, a heat alarm in the kitchen, all sounding together, plus CO alarms where there is any fixed combustion appliance or flue. Wales, under the Renting Homes (Fitness for Human Habitation) requirements in force since December 2022, also goes beyond England — including where gas cookers are concerned. Check the current Welsh government guidance for the detail; the direction of travel across the UK is unmistakably toward more alarms, better interconnection, and landlord duties that bite. Northern Ireland has no equivalent landlord alarm statute — building regulations and general duties of care apply — which makes following the other nations' guidance the sensible voluntary baseline.
What this means for everyone else
Owner-occupiers in England have no statutory alarm duty — but building-regulations guidance expects smoke alarms in circulation spaces on each storey and a heat alarm in new or rewired kitchens, and every fire service in the country recommends CO alarms wherever fuel burns. The how-many-alarms guide covers the recommended standard room by room, the common-mistakes shelf covers placement and expiry, and the monthly habit makes any of it worth having. Landlords weighing up damp duties too — which are changing around the UK right now — should read the damp-and-mould duties guide alongside this one.
Sources: The Smoke and Carbon Monoxide Alarm (England) Regulations 2015 and the 2022 Amendment Regulations (SI 2022/626); GOV.UK landlord guidance; Scottish Government fire and smoke alarm requirements. Last reviewed September 2026 · general information, not legal advice.
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General information, not professional advice. Homes differ — if a job is beyond your confidence or the guide’s boundary, that is what tradespeople are for.