Alarms are the cheapest compliance obligation a landlord has and one of the most commonly failed, because there is no certificate to chase and no annual renewal date to remind you. The duty is quiet until a local authority officer turns up.
This guide covers the rules in England, which changed on 1 October 2022 and are now the ones that apply.
How many alarms, and where
| Alarm | Where it must be | Note |
|---|---|---|
| Smoke alarm | At least one on each storey used as living accommodation | A storey counts even if it is a single converted loft room |
| Carbon monoxide alarm | Any room used as living accommodation containing a fixed combustion appliance | Gas cookers are excluded |
The two details that catch people out are both in that table. First, smoke alarms are counted per storey, not per room, so a three-storey house needs three even if two of them cover a single landing. Second, carbon monoxide alarms are triggered by fixed combustion appliances, which means gas boilers, gas fires, wood burners, oil boilers, and solid fuel stoves, but explicitly not gas cookers.
The obligation most landlords miss: the day the tenancy begins
For tenancies starting on or after 1 October 2022, you must make sure every required alarm is in working order on the day the tenancy begins. Not the week before, not when the inventory was drawn up a month earlier. That day.
This is the part that is hardest to prove after the fact, and the easiest to fix in advance. The standard approach is to test each alarm at check-in and have the tenant sign the inventory confirming they were tested and working, with the date on it. That signed line is your evidence.
Who replaces batteries, and who fixes a broken alarm
During the tenancy, replacing batteries is the tenant's job. Repairing or replacing a faulty alarm is yours, and the duty starts the moment you are told about it.
If a tenant reports an alarm that still does not work after a new battery, or reports that they cannot change the battery themselves, it becomes your responsibility to put right. There is no defined deadline in the regulations, which in practice means promptly, and a documented response matters if it is ever challenged.
What happens if you get it wrong
Enforcement runs through the local authority. If they have reasonable grounds to believe you are in breach, they serve a remedial notice giving you 28 days to fix it. Comply and that is the end of it.
Ignore it, and the authority can arrange the work itself and impose a civil penalty of up to £5,000. That figure is per breach, not a single cap per landlord or per property, so a portfolio inspected at the same time can produce several.
The wider picture on what each missed obligation costs is in our guide to landlord penalties.
Choosing alarms, briefly
The regulations do not specify a type, so this is a judgement call rather than a legal one. Two practical points:
- Ten-year sealed battery alarms remove the annual battery argument entirely and are the usual choice for single lets
- Carbon monoxide alarms have an expiry date of their own, typically 7 to 10 years from manufacture, printed on the casing. An alarm past that date counts as not working, and this is a genuinely common failure because nobody thinks to look
Note that HMOs and licensed properties may carry stricter requirements through licence conditions or a fire risk assessment, which sit on top of these rules rather than replacing them.
Turning a duty with no date into one you can track
The reason alarms get missed is structural: there is no expiry date pushing you to act. The obligation attaches to events instead, a new tenancy beginning, a tenant reporting a fault, an alarm reaching the end of its own life.
The practical fix is to give it a date anyway. Record an alarm check at the start of each tenancy and set the next one a year ahead, so it lands in the same reminder stream as your gas and electrical deadlines rather than living only in your memory. PropCert tracks a Smoke & CO alarm check as its own item for exactly this reason.
For everything else that needs a date, see the full compliance checklist, or work out your next deadlines with the renewal calculator.
Written by The PropCert team
PropCert builds certificate tracking for UK landlords. Every guide is checked against the primary source, gov.uk, HSE, or the legislation itself.
This guide is general information about landlord obligations in England, not legal advice. Where a decision turns on your specific circumstances, check the primary source or take advice.