What is a house in multiple occupation (HMO)?
A house in multiple occupation (HMO) is a property rented by at least 3 people who form more than one household and who share facilities such as a kitchen, bathroom or toilet. That's how government guidance summarises the legal test, which sits in section 254 of the Housing Act 2004. A typical example is a house shared by 4 friends, each with their own bedroom, sharing the kitchen and bathroom.
The classification isn't just jargon. Once a property is an HMO, a set of extra legal duties lands on the landlord: management standards, in many cases a council licence, minimum room sizes, and exposure to rent repayment orders if they get it wrong. For tenants, knowing you live in an HMO tells you which protections you can enforce.
What counts as a "household"?
One family, essentially. Under section 258 of the Housing Act 2004, a single household means members of the same family: couples (married, civil partners or living together) and relatives including parents, grandparents, children, brothers, sisters, aunts, uncles, nephews, nieces and cousins, with half-blood and step relationships counting.
So a couple renting a flat is one household, and the flat isn't an HMO. A couple plus a friend is two households, three people, sharing facilities: that's an HMO under the standard test. Three friends sharing are three households. Live-in employees such as au pairs are treated as part of the employer's household in some circumstances, which is one of several edge cases where it's worth checking with the council.
Purpose-built student halls managed by universities sit under separate rules and are generally outside the HMO regime for most purposes, though private student houses are firmly inside it.
When does an HMO need a licence?
Whenever 5 or more people from 2 or more households live there. Mandatory licensing has applied across England on that basis since 1 October 2018, under the Licensing of Houses in Multiple Occupation (Prescribed Description) (England) Order 2018, and there's no storey requirement: a 2-bedroom flat with 5 sharers needs a licence just as a 3-storey house does.
Smaller HMOs can need a licence too, where the council has set up an additional licensing scheme for its area (Housing Act 2004, s.56). Some councils also run selective licensing, which covers all private rented homes in a designated area regardless of size (s.80). Because the rules vary street by street, the reliable check is the public register every council must keep of the licences it has granted (s.232). Search your address, or ask the council's private sector housing team.
To get a licence, the landlord must pass a fit and proper person test and the council must be satisfied the property is suitable for the number of occupiers. Running a licensable HMO without a licence is an offence carrying an unlimited fine, with a civil penalty of up to £40,000 available to councils as an alternative (raised from £30,000 on 1 May 2026).
What rules protect HMO tenants?
Three sets, stacked on top of the rights every private tenant has:
Management standards. The Management of Houses in Multiple Occupation (England) Regulations 2006 apply to every HMO, licensed or not. The manager must display their contact details, maintain fire safety measures, keep water supply and drainage working, hold an annual gas safety certificate, have the electrical installation inspected at least every 5 years, maintain the common parts and living accommodation, and provide enough bins. Breach is a criminal offence.
Room sizes. Licences granted or renewed since 1 October 2018 carry minimum sleeping room sizes: 6.51 square metres for one person over 10, 10.22 square metres for two, 4.64 square metres for a child under 10, and no room under 4.64 square metres used as a bedroom at all.
Rent repayment orders. If the landlord commits a qualifying offence, most commonly operating an unlicensed HMO, tenants can apply to the First-tier Tribunal for a rent repayment order. Since 1 May 2026 the claim window is 2 years and the order can cover up to 2 years' rent, both doubled by the Renters' Rights Act 2025, and orders can now reach superior landlords behind rent-to-rent setups.
On top of that, the ordinary rules apply: deposits protected within 30 days (capped at 5 weeks' rent for annual rents under £50,000), landlord repair duties over the structure and the water, gas, electricity, sanitation and heating installations under section 11 of the Landlord and Tenant Act 1985, fitness for human habitation under section 9A, and council hazard enforcement under Part 1 of the Housing Act 2004. Our HMO tenant rights guide goes deeper on enforcement.
How did the Renters' Rights Act 2025 change HMOs?
The Act's first phase took effect in England on 1 May 2026 and reshaped the ground rules for every private tenancy, HMOs included:
- Section 21 is abolished. Eviction now requires a Section 8 ground; the selling and moving-in grounds need 4 months' notice and can't bite in the first 12 months of a tenancy.
- Tenancies are periodic. Sharers aren't locked into fixed terms and can leave with 2 months' notice.
- Rent rises are capped at once a year via a Section 13 notice with at least 2 months' warning, challengeable at the First-tier Tribunal before the new rent starts.
- RROs got stronger, as above, and civil penalty caps rose to £40,000.
- Deposit and database compliance now gate possession: a landlord who hasn't protected the deposit or registered on the private rented sector database generally can't get a possession order, except on antisocial behaviour grounds.
Is living in an HMO a bad thing?
Not at all, and it's how millions rent affordably. Room-by-room lets and shared houses cost less than self-contained flats, and the legal regime around HMOs exists precisely because sharing concentrates risk: more people using the same kitchen, more fire load, more wear. A licensed, well-managed HMO with a present manager is a perfectly good place to live.
The practical takeaways: check whether your house meets the 3-person, 2-household test; if it has 5 or more sharers, look it up on the council's licence register; collect the gas and electrical certificates when you move in; and report problems in writing. Everything else in HMO law builds from there.