What Is Additional HMO Licensing? A Guide for Landlords

Mandatory HMO licensing only catches the largest shared houses — five or more people forming two or more households. Additional HMO licensing plugs the gap, bringing smaller shared properties under the same regulatory framework. If your council has introduced it, every small HMO in the designated area needs a licence too.

How It Differs from Mandatory HMO Licensing

Both schemes operate under Part 2 of the Housing Act 2004, but they target different property sizes:

Mandatory HMO licensing applies nationally across all of England. Any property occupied by five or more people forming two or more separate households, who share or lack one or more basic amenities (kitchen, bathroom, toilet), needs a mandatory HMO licence. This is automatic — no council decision required.

Additional HMO licensing is discretionary. A council must formally designate an area (often the entire borough) and demonstrate that a significant proportion of smaller HMOs are being poorly managed. Once designated, every property occupied by three or four people forming two or more households and sharing amenities needs an additional HMO licence; the mandatory scheme applies at the five-or-more-person threshold.

The practical effect: in a borough with additional licensing, a flat shared by three unrelated tenants needs a licence. Without the scheme, that same flat would only need a selective licence (if one exists) or no licence at all.

Which Properties Are Covered

Additional HMO licensing applies to properties where:

• Three or four people occupy the dwelling
• Those people form two or more separate households (two unrelated friends sharing count as two households; a couple counts as one household)
• They share one or more basic amenities — a kitchen, bathroom, or toilet

The household definition matters. Under section 258 of the Housing Act 2004, a household consists of people related by blood, marriage, civil partnership, or recognised cohabitation. Two unrelated individuals living together are always two separate households, even if they share a tenancy agreement.

Purpose-built flats in blocks of three or more self-contained units are exempt from mandatory HMO licensing, but they're not exempt from additional HMO licensing. A purpose-built flat let to three unrelated sharers requires an additional HMO licence in a designated area.

Section 257 converted blocks — buildings converted into self-contained flats without complying with Building Regulations — are excluded from Barking and Dagenham's additional HMO licensing scheme at the building level. Individual privately rented flats within such blocks still need selective licences.

Fees and Conditions

Additional HMO licences are more expensive than selective licences because the compliance requirements are heavier. Fees vary by council but commonly range from £1,000 to £1,500 total, split into Part A (application) and Part B (issuance) payments.

Licence conditions for additional HMOs include everything in a selective licence plus HMO-specific requirements:

• Minimum sleeping room sizes (6.51 m² for a single adult, 10.22 m² for two adults, 4.64 m² for a child under ten)
• Adequate kitchen and bathroom facilities for the number of occupants
• Fire safety measures — mains-powered fire alarms, emergency lighting where applicable, fire doors, written Fire Risk Assessment
• Annual fire alarm and emergency lighting test certificates
• Maximum occupancy limits specified on the licence

In Barking and Dagenham, local minimums are higher for some rooms: 8.5 m² for a single bedroom with separate communal kitchen facilities, 14.0 m² for a single bedroom containing internal kitchen facilities, and 18.0 m² for a double bedroom containing internal kitchen facilities.

Why Councils Introduce It

Councils use additional licensing when they can demonstrate that a significant number of smaller HMOs in the area are being managed ineffectively enough to cause problems — poor property conditions, anti-social behaviour, or risk to tenant health and safety. The designation typically covers the whole borough and lasts five years, after which it must be renewed through a fresh consultation and approval process.

London boroughs have been particularly active. Barking and Dagenham, for example, launched its borough-wide additional HMO licensing scheme on 9 January 2025, running through 8 January 2030, alongside a concurrent selective licensing scheme.

Penalties for Non-Compliance

Operating a small HMO without the required additional licence is an offence under Section 72 of the Housing Act 2004. The consequences mirror those for mandatory HMO offences:

• Civil penalties of up to £30,000 per offence under section 249A of the Housing Act 2004; the Renters' Rights Act 2025 also allows penalties up to £40,000 for serious, fraudulent, or persistent housing breaches
• Prosecution with an unlimited fine on conviction
• Rent Repayment Orders — for offences committed on or after 1 May 2026, tenants can reclaim up to 24 months of rent; earlier offences remain subject to the previous 12-month limit
• Section 21 notices were abolished across England on 1 May 2026 under the Renters' Rights Act 2025

If your property has three or four occupants forming multiple households and your council runs additional licensing, the licence isn't optional — and applying promptly protects your ability to manage the tenancy and avoids enforcement action.

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