Who Is Responsible for Mould — Landlord or Tenant?

Mould in a rental property is stressful for everyone. Tenants worry about their health. Landlords worry about liability. Letting agents are caught in the middle. The question that comes up every time is: whose responsibility is it?

The answer depends on what's causing the mould. Here's how to work out who's responsible, what the law says, and what to do about it.

The short answer

In the UK, mould is almost always the landlord's responsibility unless it can be clearly demonstrated that the tenant's lifestyle is the sole cause. Even then, the burden of proof sits with the landlord. Blaming the tenant without evidence is a common and costly mistake.

When mould is the landlord's responsibility

The landlord is responsible for mould when it's caused by a defect in the property or a failure to maintain it. This includes:

• Penetrating damp from a leaking roof, broken guttering, or cracked render
• Rising damp due to a failed or missing damp-proof course
• Poor ventilation — if the property doesn't have adequate extractor fans or trickle vents
• Cold bridging — uninsulated external walls that create condensation points
• Plumbing leaks behind walls or under floors
• Windows that are sealed shut or don't open properly
• Previous mould that was painted over rather than properly treated

Under Section 11 of the Landlord and Tenant Act 1985, landlords must maintain the structure and exterior of the property, plus all installations for water, gas, electricity, and heating. If any of these systems contribute to damp conditions, the landlord is liable.

When mould might be the tenant's responsibility

A tenant may be responsible if the mould is caused entirely by their lifestyle choices, with no contributing structural or maintenance factors. This is a narrow exception and difficult to prove. Examples include:

• Consistently drying laundry indoors without ventilation despite adequate facilities being available
• Blocking or switching off extractor fans
• Keeping windows permanently closed in high-moisture rooms when trickle vents and extractors are available
• Overfilling a property beyond its design capacity
• Refusing access for the landlord to inspect or carry out remedial work

What the law requires landlords to do

What happens if you do nothing?

Ignoring mould complaints is one of the most expensive mistakes a landlord can make. Potential consequences include:

• Local authority improvement notices with deadlines for remediation
• Civil penalties of up to £30,000 per offence
• Prosecution for serious or persistent failures
• Rent repayment orders — tenants can claim back up to 12 months of rent
• Personal injury claims if a tenant's health is affected
• Inability to serve Section 21 notices if the property is in disrepair

The right approach

Whether you're a landlord or a letting agent, the safest approach is to take every mould report seriously and investigate promptly. A professional damp and mould survey costs from £100 and provides the documentation you need — either to demonstrate due diligence or to confirm that the cause is structural and needs fixing.

We carry out HHSRS-compliant damp and mould surveys across Lincoln and Lincolnshire through our specialist division, The Damp & Mould Man. Each survey includes thermal imaging, moisture analysis, mould classification, and a detailed written report. If remediation is needed, we handle everything from mould treatment to ventilation improvements, replastering, and redecorating.