Managing a House in Multiple Occupation (HMO) is fundamentally different from running a standard buy-to-let. Multiple tenants, individual room-by-room income streams, shared facilities, and strict compliance obligations create a level of operational and financial complexity that standard property management approaches simply cannot handle. Add Making Tax Digital (MTD) to the picture, with its mandatory digital record-keeping and quarterly HMRC submissions, and the case for purpose-built systems becomes impossible to ignore.
This guide is for HMO landlords who want to manage their multi-unit properties efficiently, stay compliant with MTD requirements, and use the right tools to protect and grow their returns.
KEY TAKEAWAYS
HMOs generate far more transactions than single lets, so manual or basic spreadsheets become risky once MTD quarterly reporting applies
In England, HMOs often need both planning consent and licensing, and safety rules add mandatory costs that are usually deductible and should be captured accurately
MTD compliance depends on clean digital records, proper digital links and separate tracking of residential finance costs for Section 24
Joint ownership is common in HMOs, so systems must handle ownership splits and joint property easements under MTD
Purpose built HMO software can provide room level income tracking, Section 24 separation and MTD submissions in one place, which generic software rarely does well
Landlords with qualifying income above £50,000 will be within MTD ITSA from April 2026, so systems and workflows must be in place in advance
What is an HMO Property?
A House in Multiple Occupation is a property occupied by three or more unrelated people who form more than one household and share facilities such as a kitchen, bathroom or toilet. This shared arrangement distinguishes HMOs from standard single lets and is a key reason why they often produce higher gross yields.
The same features that drive yield also drive complexity. More occupiers mean more rent payments, more repairs, tighter safety obligations and many more separate transactions.
For landlords within MTD, this raises both the opportunity for higher income and the risk of mistakes if systems are weak.
Legal Foundation: Licensing, Planning and Safety
Before addressing financial management, the operational foundation must be solid. Legal compliance is non-negotiable and directly affects both the viability of the investment and its tax treatment.
Mandatory Licensing Requirements
In England, any HMO occupied by five or more people forming two or more separate households requires a mandatory HMO licence from the local council. Licensing rules in Wales, Scotland and Northern Ireland differ, so landlords must check the specific requirements in the country where the property is located.
Important
Operating without a required licence can result in unlimited financial penalties and may invalidate certain expense claims. Always verify with your local authority.
Licences typically last five years and costs vary by area. Smaller HMOs may still require a licence under Additional or Selective Licensing schemes, always verify with your local authority. Operating without a required licence can result in unlimited financial penalties and invalidates certain expense claims.
Planning & Regulatory Framework
In England, HMOs are grouped into planning use classes:
Use Class C4 (SMALL HMO)
Three to six occupiers in more than one household. Many locations require planning permission due to Article 4 Directions removing permitted development rights.
Sui Generis (LARGE HMO)
Seven or more occupiers. Generally requires full planning permission to create or intensify. Always check with the local planning department before converting.
In many locations an Article 4 Direction removes permitted development rights (the ability to change use without planning permission), so even converting a single dwelling to a small C4 HMO can need planning permission.
Landlords should always check with the local planning department before starting a conversion or upsizing occupancy.
Safety and Minimum Standards
The main HMO framework comes from the Housing Act 2004 and the Management of Houses in Multiple Occupation Regulations. Fire duties sit mainly within the Regulatory Reform (Fire Safety) Order 2005, the Fire Safety Act 2021, the Fire Safety (England) Regulations 2022 for some buildings and your licence conditions.
All licensed HMOs must meet strict safety standards. As a minimum you should expect:
Mandatory Safety Requirements
Annual gas safety checks and certificates for tenants
Electrical installation inspection (EICR) at least every five years
Suitable smoke and heat alarms often interlinked
Safe escape routes and appropriate fire precautions, which may include fire doors, emergency lighting, fire blankets or extinguishers depending on local requirements and the fire risk assessment
Minimum bedroom sizes for licensed HMOs are set nationally at 6.51 square metres for one adult and 10.22 square metres for two adults
Managing Multi-Unit Tenancies Effectively
Tenancy Agreement Structures for HMOs
HMO landlords typically choose between: Individual vs Joint tenancies.
Individual ASTs
Each tenant is responsible for their own rent. Reduces exposure to full property voids and aligns well with room-level income tracking for MTD compliance.
Joint Tenancies
All occupiers jointly and severally liable. Simplifies collection but can mean all rooms go vacant simultaneously directly hitting quarterly income figures.
Tenant Screening to Protect Income Continuity
Consistent rental income is the foundation of HMO returns. Strong screening through credit checks, employer checks and previous landlord references reduces arrears and disputes. Checking compatibility with existing tenants also helps reduce churn.
Each empty room directly lowers your quarterly income figures. Keeping rooms occupied through proactive marketing, clear house rules and prompt maintenance is as much a financial and tax protection measure as it is an operational one.
Why HMOs Multi-Unit Properties Create Unique Management Challenges?
High transaction volumes
A single let may generate 12 to 24 transactions a year. A typical five bedroom HMO can easily produce 60 or more rent receipts plus over 100 expense transactions, especially where bills are included. With a small HMO portfolio you are soon dealing with several hundred entries per year across multiple properties and income streams.
Under MTD ITSA, all of these must be recorded digitally and summarised in quarterly updates. The more transactions you have, the greater the benefit of automation and the higher the risk if you rely on manual methods.
Digital links and spreadsheets
MTD requires you to keep digital records and to move data between systems using digital links. Once figures are in digital form they must flow through to submission without manual retyping or copy and paste. Acceptable links include bank feeds, APIs, CSV imports and spreadsheet formulas feeding into bridging software.
Static spreadsheets with manual copying between tabs or into tax software are not compliant. For an HMO portfolio with hundreds of entries, spreadsheets are only workable if they sit within a properly linked digital process.
Limits of generic accounting tools
Most general accounting platforms are designed for trading businesses rather than property portfolios.
Feature | Generic Software | HMO Specialist Software |
|---|---|---|
Room-level income tracking | ✗ No | ✓ Yes |
Section 24 finance cost separation | ✗ No | ✓ Yes |
HMO-specific expense categories | ✗ No | ✓ Yes |
Joint ownership handling | ✗ Limited | ✓ Yes |
Direct MTD ITSA submission | ✗ Rare | ✓ Yes |
Trying to fit an HMO portfolio into generic software often produces messy workarounds and breaks digital links, which conflicts with MTD and increases error risk.
Expense Tracking: Core to both Tax and MTD
This is where HMO management and MTD compliance intersect most directly. Expense tracking for multi-unit properties is substantially more complex than for single-let properties and getting it right is both a tax management and a compliance obligation.
HMO-Specific Expense Categories
HMOs create expense categories that do not exist in standard single lets. Common examples include:
Commonly Underclaimed Deductions
HMO licence fees under mandatory, additional and selective schemes
Fire risk assessments and fire safety works
Gas safety, EICRs and other statutory inspections
HMO specific insurance policies
Communal area cleaning and maintenance
Room specific repairs and decorations
Each category should be coded accurately in your digital system from the start. This supports correct quarterly summaries and avoids lost relief at year end.
Separating Residential Finance Costs Under Section 24
For personally owned HMOs, the Section 24 restriction on residential finance costs is one of the largest drivers of net tax. Higher and additional rate taxpayers no longer deduct mortgage interest in full from rental income and instead receive a basic rate tax credit of 20%.
To apply this correctly you must record residential finance costs separately from other expenses.
Joint ownership and allocations
Many HMO investors hold different properties with different co‑owners. For MTD you report only your share of the income and expenses each quarter.
Your software therefore needs to:
Store ownership percentages by property
Apply those splits automatically to income and expense categorie
Support joint property easements, such as the ability to report income only on quarterly updates and defer detailed expense data to year end, while still recording all transactions digitally
This reduces manual apportionment and keeps joint owners consistent.
Making Tax Digital for HMO Landlords
Who is caught and When?
Making Tax Digital for Income Tax (MTD For ITSA) applies to landlords and sole traders, who have gross qualifying income above certain thresholds. MTD requires these taxpayers to maintain digital records and submit quarterly updates and final tax return to HMRC.
MTD for Income Tax will apply from:
Qualifying income:
Total gross property income plus self employed income, including foreign property, before expenses. Employment income and pensions do not count.
