There must be working smoke alarms on every floor of a rental property which is used as living accommodation as set out in The Smoke and Carbon Monoxide Alarm Regulations.
There must also be a carbon monoxide alarm in every room used as living accommodation and where solid fuel is used. As a landlord, your obligation is to make sure that all such equipment is in working order at the start of each new tenancy.
After the initial test on the first day of the tenancy, it then becomes the tenant’s responsibility to ensure that the alarms are in good working order. It is thought that monthly testing is sufficient for the testing of the alarms.
The first date of the tenancy is the date that is referred to in the tenancy agreement, therefore even if a tenant does not take occupation on the date referred to in the agreement, the landlord must ensure that all alarms are in working order at the beginning of the tenancy