HMO licensing and Article 4: the rules that decide if the numbers work
An HMO can be the highest-yielding use of a property and the fastest way to lose money, and the difference is usually a licence you did not check for.
A house in multiple occupation is broadly a property let to three or more people who are not all from the same household and who share facilities. The definition matters because licensing, planning and management regulations all attach to it, and because a property that becomes an HMO without the necessary permissions can be forced back to a single let.
Two separate regimes apply and they are frequently confused. Planning permission controls the change of use; licensing controls the management and safety of the property once it is in use. You can hold one and not the other.
Mandatory, additional and selective licensing
Mandatory licensing applies nationally to larger HMOs — five or more occupants forming two or more households, sharing facilities. Additional licensing lets a council extend that to smaller HMOs in its area, and selective licensing lets it license any privately rented property in a designated area, regardless of occupancy.
The practical consequence is that the rules where you are buying may be entirely different from the rules where you live. There is no substitute for checking the specific council's published scheme, including its designation dates and whether it is consulting on an extension.
- Mandatory: five or more occupants, two or more households, shared amenities
- Additional: a council extending licensing to smaller HMOs, often three or four occupants
- Selective: any private rented property in a designated area, even a single household
- The licence is per property, per licence holder, and is not transferable on sale
Article 4 directions and permitted development
Converting a family house into a small HMO for three to six people has historically fallen within permitted development rights, meaning no planning application was needed. An Article 4 direction withdraws that right in a defined area, so a full planning application becomes necessary.
This is the trap. A property in an Article 4 area can be bought, converted and let, and only then be found to require planning permission that would not have been granted. Enforcement can require the property to be returned to a single dwelling, which destroys the investment case and the property's value in one decision.
The management standards that catch landlords out
Once licensed, an HMO carries management obligations that go beyond a standard let: minimum room sizes, fire safety including detection and escape routes, adequate cooking and washing facilities per occupant, and a documented management regime. Failure to comply is an offence, and some offences attract civil penalties or banning orders.
The costs of compliance are real and belong in the yield calculation. Fire doors, an upgraded alarm system, a communal kitchen refit and the licensing fee itself can add thousands, and they recur. An HMO that looks like a 9% yield on rent alone can be a 6% yield once the compliance costs are properly annualised.
Common questions
- Do I need planning permission to convert a house to an HMO?
- For a small HMO of three to six people, permitted development rights usually apply — unless the council has made an Article 4 direction removing them, which many have. Larger HMOs and flats generally need a planning application regardless. Always check the specific council's position for the specific property before you exchange.
- Can I inherit the seller's HMO licence?
- No. An HMO licence is granted to a named licence holder for a specific property and does not transfer on sale. You must apply for your own, and until it is granted letting the property as an HMO may be an offence. Budget for the gap between completion and licence grant, and check the council's processing times.