Mould rental property landlord responsibility is not a grey area under current UK law. In the great majority of cases, a landlord has a legal duty to investigate mould in a rented property and fix the cause. Three overlapping statutes - the Landlord and Tenant Act 1985, the Homes (Fitness for Human Habitation) Act 2018, and the Housing Health and Safety Rating System - have long put structural and building-related mould on the landlord. The Renters' Rights Act 2025, which came fully into force for most provisions on 1 May 2026, strengthens those duties further and gives tenants more ways to enforce them.
Understanding which laws apply and what each requires is the difference between handling a complaint efficiently and finding yourself facing a council inspector or a disrepair claim. This guide sets out the position plainly. It is general guidance, not legal advice - if you are dealing with a formal disrepair claim or enforcement notice, take proper advice on your specific situation.
The legal framework: which laws apply
Several laws overlap when it comes to mould in a rented home. You do not need to know the fine detail of each one, but knowing the names matters when a tenant or a solicitor uses them in correspondence.
Section 11 - Landlord and Tenant Act 1985
Under Section 11, landlords must keep the structure and exterior of a property in repair, and maintain the installations for heating, hot water and drainage. Where mould results from a leaking roof, a defective damp-proof course, failed windows or broken heating, it falls within this repairing duty. Critically, the duty cannot be contracted away - a clause in a tenancy agreement saying the tenant accepts responsibility for mould does not override Section 11.
Homes (Fitness for Human Habitation) Act 2018
Every rented property must be fit for human habitation throughout the tenancy. Significant damp or mould can make a property unfit, giving the tenant the right to apply directly to court for a remedy and compensation - without needing the council to act first. The 2018 Act gives tenants a private right of action that does not depend on local authority enforcement.
Housing Health and Safety Rating System (HHSRS)
The HHSRS treats damp and mould as a potential Category 1 hazard when it presents a serious risk to health. Councils use this framework to inspect properties and, where they find a significant hazard, to serve improvement notices or prohibition orders. Following updated government guidance issued in 2023, local authorities across England have been taking a more proactive approach to damp and mould in both the social and private rented sectors.
The Renters' Rights Act 2025
The Renters' Rights Act 2025 came fully into force for most provisions on 1 May 2026. For private landlords dealing with mould, the key changes are: the Decent Homes Standard has been extended to the private rented sector for the first time, requiring private rented homes to meet minimum condition standards; a Private Rented Sector Ombudsman is being established, giving tenants an out-of-court route to get landlords to act; and Section 21 no-fault evictions were abolished, removing the risk of retaliatory eviction for tenants who report maintenance problems including mould.
Awaab's Law
Awaab's Law has been in force for social landlords - housing associations and local authority housing departments - since 27 October 2025. It sets fixed timescales: emergency hazards must be made safe within 24 hours; significant damp and mould must be investigated within 10 working days, written findings sent to the tenant within 3 working days of completing that investigation, and all necessary safety works completed within 5 working days of the investigation. The Renters' Rights Act gives ministers the power to extend these timescales to private landlords. That extension has not been confirmed as of July 2026, but it is expected during 2026-2027 - check the current government guidance for the latest position before relying on a specific date.
What these laws require from you in practice
Taken together, the laws create clear practical obligations for any landlord who receives a report of mould. Acting on them promptly also gives you the best protection if a claim ever follows.
- Respond to any mould report in writing, promptly. Do not delay or dismiss it without investigation.
- Inspect the property to find the actual cause - a leak, damp, cold spot, inadequate ventilation - not just the visible patch of mould.
- Fix the underlying cause, not just the surface. Treating the mould without addressing the moisture source means it returns, and the tenant has a clear record of a failed repair.
- Improve what needs improving: working extractor fans, trickle vents, adequate heating, insulation where the building is cold and damp follows from that.
- Keep written records throughout - dates of report, date of inspection, what you found, what works were done and when. Good records are your strongest protection in any enforcement or disrepair action.
When is mould not the landlord's responsibility?
There is a narrow band where mould is genuinely caused by tenant behaviour rather than the building - for example, drying large quantities of washing on radiators with all windows shut and extractors blocked, in a property that is otherwise warm, well-insulated and properly ventilated. Even in that situation, a landlord cannot simply blame lifestyle and walk away without investigating.
Councils and courts have become sceptical of the lifestyle defence. If the walls are cold, the property has no working extraction, and the windows are difficult to open, the building cannot cope with normal household moisture and responsibility shifts back to the landlord. The safe approach is always to investigate the actual cause rather than assuming it is the tenant. For a detailed look at what causes mould in a property and how to distinguish building problems from tenant behaviour, see our separate guide.
What happens if a landlord ignores a mould report
Ignoring a mould report exposes a landlord to several overlapping risks, all of which are growing more serious under the current legal framework.
- Council enforcement: the local authority can inspect under the HHSRS and serve an improvement notice requiring works within a fixed period. Failure to comply can result in substantial fines.
- Housing disrepair claim: the tenant can apply to court for an order that repairs be done, plus compensation for the period they lived in an unfit property. Legal costs frequently dwarf the cost of the original repair.
- PRS Ombudsman: once established, the Private Rented Sector Ombudsman will be able to order landlords to take action and pay compensation without the tenant needing to go to court.
- The problem gets worse and more expensive: left untreated, mould spreads and the underlying moisture causes further damage to plaster, joinery, and eventually structure. A repair costing a few hundred pounds early on becomes a major remediation job if ignored.
How to respond when a tenant reports mould
A clear, documented response protects both the tenant and your position as a landlord. Here is what a sound response looks like:
- Acknowledge the report in writing on the day you receive it.
- Arrange an inspection within a few working days - do not let it drift.
- Identify the cause properly: a damp meter reading, a check of the roof, gutters and plumbing, and a look at extraction and ventilation will tell you what is driving the moisture.
- Instruct works to fix the cause first, then treat the mould properly. Surface cleaning without addressing the cause creates a paper trail of failed repairs.
- Confirm the completed works in writing to the tenant and keep copies of all correspondence, inspection notes and invoices.
How Simpled Services helps landlords stay compliant
We deal with mould reports for housing associations, councils, letting agents and private landlords across London and the South of England every week. As a Constructionline Gold accredited contractor we are fully insured and have completed over 8,500 jobs. When we treat mould, we identify and address the cause first - damp, leaks, cold spots, or failed ventilation - and we back our mould work with a 12-month guarantee. Sending a photo on WhatsApp is the fastest way to get a quote and we can usually give you an indicative price from the pictures before we even visit.
If you need a hand, Simpled Services can help. Call us on 020 4571 7367, message us on WhatsApp at the same number (020 4571 7367), or email hello@simpledservices.co.uk and we will take it from there.