Definition of a Small HMO
A small HMO essentially refers to a property that meets the criteria to be defined as an HMO property but does not require a mandatory HMO licence under UK regulations. These criteria include:
- 3-4 or more unrelated tenants living in the same dwelling, forming more than one household
- Tenants sharing the use of facilities such as kitchens, living spaces and bathrooms
Once a property with this criteria reaches 5 or more unrelated tenants, it is then classified as a Large HMO and therefore the landlord must obtain a mandatory HMO licence in order to operate the property.
It’s worth noting that some local councils may require an additional HMO licence even for small HMOs, despite them not requiring the standard mandatory licence. However, it’s worth checking with your specific planning council on whether this applies in your local area.
Large HMOs vs Small HMOs: Key Differences
The key difference between Small vs Large HMOs tends to be down to the number of occupants in your HMO. As a rule of thumb, 3-4 tenants is a “Small HMO” and anything with 5+ occupants is a “Large HMO”. Our comparison table breaks this down in more detail if you’re not sure:
| Small HMOS | Large HMOs | |
| Number of Tenants | 3-4 Tenants | 5+ Tenants |
| Use Class | C4 | C4 – Sui Generis for 7+ occupants |
| Mandatory Licence Required | No Additional Required in some areas* | Yes |
| Planning Requirements | C3 – C4: Allowed under Permitted Development Rights Article 4 directions apply | C3 – C4: Allowed under Permitted Development Rights C3/C4 – Sui Generis: Planning Application required Article 4 directions apply |
Licence Requirements for Small HMOs
The mandatory HMO licence is not required for Small HMOs as it only applies to HMOs that are 5 or more unrelated tenants. However, some areas in the UK require an additional HMO licence which can still apply to Small HMOs.
The following areas in the UK have additional licencing regulations, though regulations change frequently and it’s always best to check the latest licencing rules on the appropriate council websites:
London Boroughs with Additional HMO Licensing
- Lambeth – Additional HMO licencing was introduced on 8 September 2021.
- Enfield – Additional licencing started in the borough on 1 September 2020.
- Barnet – A borough-wide additional licensing scheme started on 27 October 2022 and will end on 27 October 2027 (or earlier if the council revokes the scheme.)
- Camden – This is a local scheme to Camden which came into force on 8 December 2020. This replaces the additional licensing scheme introduced in 2015.
- Southwark – Operates additional and selective licencing schemes.
- Newham – The additional HMO licensing scheme was launched on 1 January 2023.
- Hammersmith & Fulham – Operates an additional HMO licencing scheme.
- Tower Hamlets – The whole Borough of Tower Hamlets is an area with additional licensing requirements.
- Waltham Forest – Launched the scheme in April 2020, to cover properties occupied by three or more people outside of mandatory HMO licensing.
It’s worth noting that Brent did require an additional licence for all HMOs but this scheme came to an end on 31st January 2025.
Major Cities & Areas with Additional HMO Licensing
- Birmingham (large parts of the city require small HMO licenses)
- Nottingham (Selective and Additional Licensing schemes)
- Bristol (applies in certain areas like Bedminster and Brislington West)
- Oxford (citywide licensing for all HMOs)
- York (additional licensing applies to 8 wards)
- Coventry (applies to the whole city)
- Southampton (additional licencing in 4 wards)
Room Size Requirements for Small HMOs
Bathroom Requirements for Small HMOs
While restrictions can vary from council to council, in general the ratio is 1 bathroom for every 4 tenants. This means that Small HMOs will require 1 bathroom with a toilet.
While these are the legal requirements, we recommend more bathrooms to make life more comfortable and easier for your tenants. Property Investments UK recommends using a one-bathroom-per-three-tenants ratio.
Some local councils require minimum sizes for facilities in the bathrooms, like basins and shower units. It’s worth checking with the appropriate local council to know if your Small HMO must adhere to minimum bathroom facility requirements.
Kitchen Requirements for Small HMOs
If you are operating a small HMO, you will need to make sure you adhere to the minimum kitchen requirements. We have detailed these in the table below.
Note that this table refers to Small HMOs with less than 5 tenants. Those with 5+ tenants have different requirements:
| Factors | Minimum Requirement |
| Kitchen size | 7m2No smaller than 1.8 metres across the narrowest area of the room |
| Cooking facilities | A 4 ring cooker, oven and grill |
| Worktop size | 2m x 0.6m |
| Food cupboards & storage | 70cm x 60cm x 50cm |
| Sink & drainer | 1 single sink with a drainer |
For more information, read our full article on HMO room size requirements >
Bedroom Requirements for Small HMOs
As a landlord, you are responsible for ensuring that your Small HMO bedroom sizes are in line with the guidelines outlined in The Housing Act 2004. When measuring up your bedrooms, you must ensure they meet the following minimum sizes:
| Occupancy | Minimum Bedroom Size for HMO |
| One child under the age of 10 | 4.64 square metres |
| One occupant over 10 years of age | 6.52 square metres |
| Two occupants over 10 years of age | 10.22 square metres |
Other considerations for Small HMO investment
When it comes to choosing to invest in Small HMOs, there are some major things that need to be taken into account.
Location
Consider the location for your Small HMO. Cities with strong student, professional, or transient populations are good, as well as areas with good transport links and amenities.
Cost vs Return
You should consider the total cost of the property purchase, licence, conversion costs and ongoing management compared with your total expected retinal income to ensure a strong rental yield. An HMO feasibility checker can help you calculate this.
Article 4
If you are looking to invest in a Small HMO in a city, it’s best to check on whether there are Article 4 directions in place before you look to invest. We have a full guide on Article 4 Directions >
Finance
If you are looking to finance a Small HMO, you will want to ensure you are obtaining a finance option that is most suitable for a Small HMO. Lenders offer specific HMO mortgages, so ensure you’re clued up on HMO financing >.
Cost vs Return
You should consider the total cost of the property purchase, licence, conversion costs and ongoing management compared with your total expected retinal income to ensure a strong rental yield. An HMO feasibility checker can help you calculate this.
