Learn more about how HMOs are categorised in various Use Classes.

use classes for hmos hmo guides

Use Classes for HMOs

The Town and County Planning (Use Classes) 1987 Order didn’t indue a special Use Class for HMOs, regardless of the number of tenants. However, this order was amended in 2010 to include a standalone Use Class for HMOs.

Class C4 – Houses in Multiple Occupation

“small shared houses occupied by between three and six unrelated individuals, as their only or main residence, who share basic amenities such as a kitchen or bathroom.”
C4 is the special Use Class for all HMOs in which the number of tenants is no more than 6 (with rare exceptions as explained below). In accordance with this Use Class, the range of planning permissions required for HMOs has been greatly reduced to enable the development of new HMOs in response to the increasing demand for this type of property.

Class C3 – Dwellinghouses

This class is formed of 3 parts, but the part relevant to HMOs is C3 (c)


“allows for groups of people (up to six) living together as a single household. This allows for those groupings that do not fall within the C4 HMO definition, but which fell within the previous C3 use class, to be provided for i.e. a small religious community may fall into this section as could a homeowner who is living with a lodger.”

This is a special Use Class enforced at the discretion of the local council. A residential property in which no more than 6 tenants live ‘as a single household’, even though they aren’t necessarily related (please refer to ”What is an HMO” for relevant definitions), can be allotted a special Use Class ‘C3 (c)’, provided that the property previously fell within the broader Use Class C3 (dwellinghouse).

For example, a group of 5 foreign exchange students can qualify to be regarded as a ‘single household’ in special cases, allowing an HMO to be allotted the Use Class C3 (c), instead of C4.

A developer/landlord can benefit from certain advantages such as exemption from licensing fees, or reduced rental taxes when the property falls under the Use Class C3 (c).

  • If a dwellinghouse is converted into an HMO for 4 tenants with multiple households, it falls under the Use Class C4.
  • If a block of self-contained flats is rented out to 8 unrelated tenants, it does not fall under any specified Use Class. This means that such HMOs will be assigned an ad-hoc Use Class (Sui Generis) and will invariably require planning permission.

HMO Use Classes and Planning Permission

Just like Use Classes, planning permission for the development or refurbishment of HMOs are subject to numerous criteria.

The most important point to note is that landlords and developers are not required to obtain planning permission for any structural work to a residential property that entails the change of Use Class from C3 to C4 (from a dwellinghouse to an HMO) and vice-versa (so long as the local council hasn’t invoked the Article 4 Direction .)

HMOs housing more than 6 tenants no longer fall within the Use Class C4, it becomes mandatory for such HMOs to obtain relevant the planning permission.

Please visit “HMO Planning Permission” page to read in more details what permitted planning for HMOs is, and whether your HMO project qualifies for it.

Check the facts!

If you’re planning on converting your house into an HMO to establish a steady stream of regular income, or you want to develop a property into a fully-fledged commercial HMO, you need to know which Use Class will apply BEFORE you start any work, or even agree to purchase a property.

Failure to determine all the facts and establish exactly IF an HMO can be developed in an area and if so, what size and type of HMO, can result in substantial financial consequences, so we advise clients to always check with the local council before committing to any project.