Damp and mould in rental properties: what landlords need to know

As temperatures fall and homes remain closed for longer periods, damp, condensation and mould can become increasingly apparent. For landlords, identifying the early warning signs and dealing with the underlying cause promptly can help protect tenants, prevent more extensive damage and avoid costly repairs.

Understanding the type of damp affecting a property is the first step towards finding the right solution. In this guide, we explain the most common causes, outline landlords’ responsibilities and share practical measures that can help reduce the risk of mould developing.

What are the main types of damp?

Although the symptoms can appear similar, damp generally falls into three categories. Each has a different cause and requires a different approach.

Rising damp

Rising damp occurs when moisture from the ground travels upwards through the walls of a property. It is often associated with a missing, damaged or ineffective damp-proof course, although other defects can sometimes produce similar symptoms.

Typical signs include staining or a visible ‘tide mark’ towards the bottom of a wall, peeling decoration, crumbling plaster and damage to skirting boards. It generally affects basements and ground-floor rooms and may become more noticeable during the colder months.

Because rising damp can be confused with other moisture problems, a professional assessment is advisable before committing to remedial work.

Penetrating damp

Penetrating damp is caused by water entering a property through a defect in its exterior. Common causes include damaged roof tiles, defective guttering, deteriorated pointing, cracked render and poorly sealed windows or doors.

It will usually appear on external walls or ceilings as a defined damp patch and may become more prominent during or after heavy rainfall. Resolving the external defect is essential; treating the internal decoration alone will not prevent the problem from returning.

Condensation

Condensation is one of the most common causes of damp and mould in residential property. It forms when warm, moisture-laden air meets a colder surface, such as a window, external wall or poorly insulated corner.

Black mould may then develop around windows, behind furniture, inside cupboards or in kitchens and bathrooms. Condensation is particularly common in winter, when ventilation is reduced and surfaces are colder.

Its cause is not always straightforward. Heating, insulation, ventilation, the condition of the property and the way the home is used can all play a part. Landlords should therefore investigate the full picture rather than assuming the problem is solely the result of a tenant’s lifestyle.

Who is responsible for damp and mould?

Responsibility will depend on the cause of the problem. Under the Landlord and Tenant Act 1985, landlords are generally responsible for keeping the structure and exterior of a rental property in repair, as well as maintaining installations for water, sanitation and heating. This means that damp caused by problems such as a leaking roof, defective guttering, damaged brickwork or inadequate building systems will usually require action from the landlord.

Landlords must also ensure that their properties remain fit for human habitation. Damp and mould can affect respiratory health, worsen existing conditions and have a wider impact on a tenant’s wellbeing, so every report should be taken seriously.

Tenants can play an important role by reporting problems promptly and using the property’s heating and ventilation facilities appropriately. However, advice about reducing moisture should support—not replace—a proper investigation into defects, inadequate ventilation or other underlying causes.

Does Awaab’s Law apply to private landlords?

Awaab’s Law came into force for the social rented sector in England on 27 October 2025. It introduced fixed timescales for social landlords dealing with emergency hazards and significant damp and mould hazards.

Where an emergency hazard is suspected, social landlords must investigate and make the property safe within 24 hours. Potential significant hazards must be investigated within 10 working days, with the home made safe within five working days of the investigation concluding. A written summary will generally be required within three working days.

These statutory timescales do not currently apply to private landlords. However, the Renters’ Rights Act 2025 provides for Awaab’s Law to be extended to the private rented sector. The Government is consulting on the detailed requirements and timetable, with its official consultation stating that 2027 is the earliest feasible implementation date. A final start date has not yet been confirmed.

In the meantime, the principles behind the law—taking reports seriously, assessing risks promptly, communicating clearly and addressing the root cause—provide a valuable standard for every landlord.

What should you do when a tenant reports mould?

There is no single response time that applies to every damp or mould report in the private rented sector. The appropriate urgency will depend on the severity of the problem, the potential health risk and the circumstances of the household.

As soon as a concern is raised, landlords or their managing agents should:

• Acknowledge the report and record the details, including photographs where available.

• Consider whether anyone in the household may be particularly vulnerable to the effects of damp and mould.

• Arrange an inspection promptly to identify the source and assess the extent of the problem.

• Use an appropriately qualified contractor or specialist where the cause is unclear.

• Remove visible mould safely while also addressing the underlying defect.

• Give the tenant clear information about the proposed work and expected timescales.

• Keep records of inspections, correspondence and completed repairs.

• Revisit the property after remedial work to confirm that the treatment has been effective.

Simply cleaning or painting over mould is unlikely to provide a lasting solution. The source of the excess moisture must also be found and resolved.

The Government’s guidance on the health risks of damp and mould and its Housing Health and Safety Rating System guidance provide further information for housing providers.

How can landlords help prevent condensation and mould?

Prevention begins with ensuring that the property itself supports effective heating and ventilation. Regular inspections provide an opportunity to check that extractor fans, trickle vents, heating systems, windows and insulation are working as intended.

Landlords should also look for cold spots, plumbing leaks and areas of inadequate ventilation before they develop into more serious problems. Where recurring condensation is identified, improvements to extraction, insulation or energy efficiency may be required.

Tenants can be encouraged to take practical steps to manage everyday moisture, including:

• Using extractor fans when cooking or showering.

• Keeping kitchen and bathroom doors closed while these rooms are in use.

• Covering pans and avoiding leaving kettles boiling unnecessarily.

• Drying laundry outside where possible, or in a well-ventilated room with the door closed.

• Keeping vents clear and opening windows when it is safe and practical to do so.

• Leaving a small gap between furniture and external walls to allow air to circulate.

• Maintaining a reasonably consistent indoor temperature where possible.

• Reporting persistent condensation, damp patches or mould at an early stage.

These measures can help, but they should never be used as a substitute for repairing defects or improving inadequate heating, insulation and ventilation.

Using technology to stay one step ahead

Advances in property technology are making it easier for landlords to identify potential risks before visible signs of damp or mould appear.

To help landlords adapt to these changing expectations, Hawes & Co now offers a Mould Protection Device service.

Using a discreet wireless monitor installed within the property, the system tracks environmental conditions such as humidity, air quality and potential mould risk, providing regular reports that highlight changing conditions over time.

This valuable insight enables landlords and property managers to investigate potential issues sooner, helping reduce the likelihood of costly repairs while also creating a historical record of environmental data that can support compliance and assist should tenancy disputes arise.

Rather than replacing routine inspections, the service enhances them by providing greater visibility between visits and supporting a more proactive approach to property management.

If you'd like to know more about how our letting agents can help you stay compliant in a shifting rental landscape please contact our team today.

 This article provides general information and does not constitute legal advice. Requirements may vary according to the tenancy and individual circumstances. Landlords should consult current government guidance and obtain professional advice where necessary.