Who is responsible for damp, mould and condensation in a rental property?

Last updated 8th September 2023 - publication of government guidance on damp and mould growth

Damp and mould are among the most common issues in landlords may face in their rental properties. This guide explains what each one is, who is responsible for what, the legal duties landlords need to be aware of, and the steps both parties should follow when an issue is reported.

In most cases the landlord is responsible for fixing damp and mould caused by the condition of the property, while tenants share responsibility for managing day-to-day moisture through ventilation, heating and reporting issues early. Government guidance is clear, however, that tenants should not be blamed for damp and mould and that landlords must investigate the underlying cause before deciding what action is required.

For wider guidance on looking after your rental, visit our property management hub, where you'll find detailed resources on repair obligations, the Homes (Fitness for Human Habitation) Act 2018, the Housing Health and Safety Rating System (HHSRS), and our dedicated condensation guidance.

How to identify mould in a rental property

Mould is usually visible long before it becomes dangerous, but it often starts in places people don't look. Routine inspections — and clear advice to tenants on what to report — are the most reliable way to catch it early.

Common signs to look for:

• Black, green, white or pink patches on walls, ceilings or sealant. This will often start small and spread outward.
• A persistent musty smell, even when surfaces look clean.
• Peeling wallpaper, blistered paint or staining on plaster.
• Discoloration on or behind soft furnishings, mattresses and curtains.
• Condensation pooling on windows, especially in the morning.

The areas most prone to mould are:

• bathrooms,
• kitchens,
• windows,
• on external walls in unheated rooms,
• behind large pieces of furniture pushed against external walls, and,
• on upstairs ceilings if there is a roof, gutter or brickwork defect above.

Inspecting every six to twelve months gives you the best chance of catching problems before they escalate. For small areas caused by a clear, easily fixed issue such as a lack of ventilation, cleaning may be enough. Where there is a larger or recurring problem more thorough testing or the help of a qualified specialist may be needed.

What causes damp and mould?

Damp and mould rarely have a single cause. Most cases involve a combination of building defects, ventilation issues and everyday moisture. This is why blaming a party to the agreement without investigating the cause thoroughly first is rarely accurate.

Common causes include:

• Structural defects. Damaged roof tiles, faulty guttering, cracked brickwork, failed pointing or a missing damp-proof course allow water in from outside.
• Poor or insufficient insulation. Cold walls, single-glazed windows and uninsulated lofts create cold surfaces where moisture condenses.
• Inadequate ventilation. Blocked or missing extractor fans, sealed-up trickle vents and windows that are rarely opened trap moist air inside the home.
• Inadequate or inconsistent heating. Higher-than-normal moisture levels cannot escape when surfaces remain too cold; this becomes more prevalent in winter when tenants are also less likely to open windows.
• Everyday activities. Cooking, showering, drying clothes indoors and even breathing release significant moisture into the air. Without ventilation, this moisture has nowhere to go.
• Plumbing leaks. Slow leaks behind walls, under sinks or from poorly sealed bathrooms can saturate plaster and timber for months before being noticed.

Are landlords responsible for damp, mould and condensation?

The short answer: yes, in almost all cases where the cause relates to the property itself, but the way responsibility breaks down depends on the type of issue.

• Damp. Where damp is caused by rising or penetrating water, a structural defect or a failure to maintain the building, liability sits with the landlord under Section 11 of the Landlord and Tenant Act 1985.
• Mould. Where mould stems from rising or penetrating damp, the landlord is responsible. Where it stems from condensation, the picture is more nuanced. Government guidance is explicit that tenants should not be blamed, and landlords must investigate the underlying cause rather than assuming "lifestyle" is to blame.
• Condensation. Condensation that results from inadequate ventilation, poor insulation or insufficient heating provision is the landlord's responsibility to address. Condensation that arises despite an adequately ventilated, heated and maintained property is partly a shared responsibility — tenants need to ventilate the property, avoid drying clothes indoors without ventilation and wipe down condensation when it appears.

Prevention is best treated as a partnership: the landlord provides a property that is structurally sound, ventilated and insulated. Then, the tenant uses it in a way that doesn't create unnecessary moisture and reports any issues promptly.

What legal responsibilities do landlords have regarding damp, mould and condensation?

Several pieces of legislation place clear duties on landlords:

• Section 11 of the Landlord and Tenant Act 1985. Landlords must keep the structure and exterior of the property in repair, including walls, roofs, windows and drains. If these elements are defective, they can cause penetrating and rising damp.
• The Homes (Fitness for Human Habitation) Act 2018. Properties must be fit for habitation throughout the tenancy. Serious damp and mould render a property unfit, and tenants can take landlords directly to court if it is not addressed.
• The Housing Health and Safety Rating System (HHSRS). Damp and mould are recognised hazards. Local authorities can inspect properties and serve improvement notices, hazard awareness notices or, in serious cases, prohibition orders.
• Awaab's Law. It will introduce strict, legally enforceable timeframes for landlords to investigate and resolve damp, mould and other serious hazards. Whilst it is already in force in social housing since 27 October 2025, it is not clear when it will apply to the PRS as a consultation is still awaited.
• The Decent Homes Standard. Also being extended to the PRS through the Renters' Rights Act 2025, the standard will require properties to be free from serious hazards and to meet new thermal comfort requirements. This is not expected to apply in full until 2035.

Penalties for serious or repeat non-compliance can reach £40,000 in civil penalties, with criminal prosecution also available to local authorities in the most serious cases.

The process of dealing with damp and mould between landlords and tenants

Following a clear, documented process protects both parties. The steps below outline best practice from the moment an issue is noticed to its resolution.

1. Tenant reports the issue in writing. The tenant should notify the landlord or letting agent as soon as they notice damp, mould or persistent condensation. A written report (email, message through a portal, or letter) creates a clear timestamp.
2. Landlord acknowledges promptly. Acknowledge the report quickly, confirm next steps and set expectations on timing. Keeping the tenant informed throughout is a core part of government guidance.
3. Inspect and investigate the cause. Arrange an inspection without unreasonable delay. For complex or recurring cases, a specialist damp survey, thermographic imaging or microbial sampling may be needed.
4. Document everything. Photograph affected areas, log communications and keep a record of any specialist reports. This evidence is invaluable in deposit disputes and any local authority involvement.
5. Decide on remediation. Small surface areas may be cleaned with an anti-fungal product. Larger infestations, recurring problems or anything caused by a structural defect should be handled by a qualified professional.
6. Carry out the works. Address the underlying cause first — structural repairs, improved ventilation, better insulation — and then deal with the visible damage.
7. Provide tenant guidance. Share clear advice on how to reduce condensation and prevent mould returning, such as the NRLA's condensation factsheet.
8. Follow up. Re-inspect after any remedial work to check that the mould has not returned, and add a follow-up to your inspection schedule for the next six to twelve months.

How to deal with damp

The NRLA's recommended approach is to treat damp, mould and condensation as three connected problems with the same underlying principle: find the cause, fix it, then deal with the visible damage.

• For damp. Diagnose the source before treating the symptom. Rising damp usually needs a damp-proof course specialist; penetrating damp needs the external defect (roof, guttering, brickwork) repaired; plumbing leaks need a plumber. Treating walls without fixing the source rarely lasts.
• For mould. Document the affected area with photographs. Small patches of surface mould — for example a bathroom ceiling spot — can often be cleaned with a household mould remover or mild bleach solution by anyone properly equipped to do so. Larger or recurring infestations should be handled by a professional. After cleaning, identify and fix the underlying moisture source, otherwise the mould will return.
• For condensation. Improve ventilation (extractor fans vented to the outside, open trickle vents, brief daily window opening), maintain adequate heating throughout the property, and address cold-bridging through better insulation. Provide tenants with a copy of the NRLA's condensation factsheet so they understand the day-to-day habits that help.

Whatever the cause, act promptly. Government guidance published in 2023 makes clear that landlords must take damp and mould seriously, assess the underlying causes with urgency, take appropriate action and keep tenants informed throughout.

How landlords can prevent condensation and mould

Prevention is significantly cheaper and less stressful than remediation. The following practices, drawn from NRLA guidance and current industry best practice, reduce the risk of damp, mould and condensation becoming a problem in the first place.

• Provide adequate ventilation. The property should be ventilated throughout so that ordinary use doesn't require windows to be opened constantly or cause excess moisture build-up. Install and maintain extractor fans vented to the outside in kitchens and bathrooms, with bathroom fans on a timer. Make sure trickle vents in windows are open and unobstructed.
• Maintain effective heating. A consistently and adequately heated property stops walls and windows from becoming the cold surfaces where condensation forms. This is particularly important in winter and when the property is left unoccupied.
• Invest in insulation. Loft insulation, cavity wall insulation and double glazing reduce cold-bridging and the cold surfaces that condensation needs to form. Where insulation is added, ensure ventilation is upgraded to match.
• Educate your tenants. Provide clear guidance on reducing condensation: opening windows for an hour or so a day even in colder months, not drying washing directly on radiators without ventilation, leaving a gap behind furniture against external walls, and wiping condensation away as soon as it appears.
• Carry out regular inspections. Inspect the exterior every six to twelve months for guttering, brickwork and roof issues, and check interior high-risk areas for early signs of damp or mildew during mid-tenancy visits.
• Use anti-mould products where appropriate. Anti-mould paint in bathrooms, kitchens and laundry areas provides an additional layer of protection in high-moisture rooms.
• Make reporting easy. Tenants are far more likely to flag issues early when there is a clear, simple route to do so. Act on reports promptly to stop small problems escalating into hazards or costly repairs.

How we can help you

Managing damp, mould and condensation in a rental property is rarely simple, especially with new legislation on the horizon. The NRLA is here to make it manageable.

As a member, you get access to our expert landlord advice line for unlimited guidance on damp and mould issues, downloadable factsheets you can share with your tenants, our Damp and Mould Awareness eLearning course, property management tools through Portfolio, and exclusive discounts on specialist services.

Join the NRLA today and get the support you need to stay compliant, protect your tenants and safeguard your investment.

Is a landlord obligated to fix damp or mould in a rental property?

Yes. Under the Homes (Fitness for Human Habitation) Act 2018, landlords must ensure their property is fit for habitation throughout the tenancy, which includes being free from serious damp and mould. Section 11 of the Landlord and Tenant Act 1985 places further duties on landlords to keep the structure and exterior in repair, and damp and mould are recognised hazards under the HHSRS — meaning a local authority can take enforcement action, including civil penalties of up to £40,000 for serious or repeat breaches.

Does Awaab's Law apply to all landlords?

Not yet. Awaab's Law has been in force in social housing in England since 27 October 2025, requiring social landlords to investigate damp and mould within fixed timescales and address emergency repairs within 24 hours. The Renters' Rights Act 2025 extends Awaab's Law to the private rented sector, but the detailed timeframes for PRS landlords will be set out in secondary legislation following government consultation. It is still unclear when this consultation will take place.

How can landlords prevent mould caused by condensation?

The most effective prevention combines four things: adequate ventilation (extractor fans, trickle vents and regular window opening), consistent heating that keeps wall surfaces warm enough to prevent condensation forming, good insulation to reduce cold-bridging, and clear tenant guidance on day-to-day habits such as not drying clothes on radiators and wiping away condensation when it appears. Regular inspections and prompt action on tenant reports stop small condensation issues from turning into mould.

How do you tackle black mould in a rental property?

Start by documenting the problem with photographs and notes. For small surface patches, clean with an anti-fungal spray or a mild bleach solution, wearing gloves, eye protection and a suitable mask. For larger, recurring or hidden mould you should engage a qualified mould specialist. Crucially, identify and fix the moisture source (a leak, a structural defect, inadequate ventilation or heating) at the same time, otherwise the mould will return. Re-inspect after the work is complete and add a follow-up check to your inspection schedule.