Written by
Sarah Nguyen
Published on
Jan 16, 2026
Damp and mould make up half of all complaints received by the Housing Ombudsman. It's the single biggest source of maintenance disputes — and the issue most likely to result in legal action, regulatory intervention, or reputational damage if handled badly.
The good news: most damp and mould cases are manageable if you respond properly. The bad news: "properly" now means following a clear process, documenting everything, and treating tenant reports seriously from day one.
Here's how to do it right.
Don't Dismiss It as "Lifestyle"
Let's start with what not to do.
For years, some landlords and agents defaulted to blaming tenants for damp and mould — suggesting it was caused by not opening windows, drying clothes indoors, or keeping the heating too low. That approach is no longer acceptable.
Government guidance is explicit: landlords should never assume damp and mould is caused by tenant behaviour. Everyday activities like cooking, bathing, and drying laundry unavoidably produce moisture. If a property can't handle normal living without developing mould, that's a building issue, not a tenant issue.
The onus is on the landlord to investigate the cause — not to assume tenant fault and close the case.
This matters legally too. The Housing Ombudsman has repeatedly found against landlords who dismissed mould complaints as "condensation caused by lifestyle" without proper investigation. Courts take a similar view. If your defence is "the tenant should have opened more windows," you're probably going to lose.
The Response Timeline You Should Follow
When a tenant reports damp or mould, here's the timeline to aim for:
Within 24 hours: Acknowledge the report
Confirm you've received it. Let the tenant know you're taking it seriously and will investigate. If they've sent photos, say you've seen them. This sounds basic, but many complaints escalate simply because tenants feel ignored in the first few days.
Within 5 working days: Arrange an inspection
Sooner if the tenant has raised health concerns or there are vulnerable people in the household. The purpose of this visit is to assess the severity, identify the likely cause, and determine what action is needed.
At the inspection: Gather the right information
How extensive is the mould? Surface patches, or covering walls and ceilings?
Where is it located? Bathrooms and kitchens (high moisture) vs bedrooms and living rooms (more concerning)?
Are there signs of water ingress — leaks, staining, damp patches?
Is the ventilation adequate? Do extractor fans work? Can windows open?
Is the heating system functional?
Who lives in the property? Children, elderly, anyone with respiratory conditions?
Take photos. Lots of them. These form part of your audit trail and may be needed later.
Within 3 working days of inspection: Provide a written summary
Under Awaab's Law (currently applying to social housing), landlords must give tenants a written summary of what was found and what will be done. Even if you're managing private rentals, this is good practice — it sets expectations and creates a record.
Within a reasonable timeframe: Complete remedial works
What's "reasonable" depends on the severity. Surface mould that can be treated with a mould wash might be resolved in days. Structural issues causing penetrating damp might take weeks. If the fix is complex, provide interim measures — dehumidifiers, mould treatment, temporary ventilation solutions — and keep the tenant informed of progress.
Triage: Is This an Emergency?
Not all damp and mould cases are equal. Some require urgent action. Signs that a case might be an emergency:
Extensive mould covering large areas of walls or ceilings
Vulnerable occupants — a child under 5, someone elderly, anyone with asthma, COPD, or a weakened immune system
Visible water ingress — an active leak, water coming through walls or ceilings
Tenant explicitly stating health impact — "my child's asthma has got worse," "I'm struggling to breathe"
If any of these apply, treat it as urgent. Under Awaab's Law, emergency hazards must be investigated and made safe within 24 hours. Even for private rentals, sitting on a case where a tenant has flagged health concerns is asking for trouble.
When in doubt, escalate. It's far better to over-respond to a case that turns out to be minor than to under-respond to one that escalates.
Investigation Checklist
When you inspect — or when you brief a contractor or surveyor — here's what to check:
Ventilation
Do extractor fans work in the kitchen and bathroom?
Are windows openable? Do tenants have trickle vents?
Is there adequate airflow, or is the property sealed tight?
Leaks and water ingress
Any signs of roof leaks, damaged guttering, or blocked downpipes?
Leaking pipes — under sinks, behind bath panels, in airing cupboards?
Water staining on ceilings or walls suggesting historic or ongoing leaks?
Heating
Is the heating system functional?
Can the tenant afford to heat the property adequately? (Fuel poverty contributes to condensation)
Are radiators working in all rooms?
Rising damp vs penetrating damp vs condensation
Rising damp: typically affects ground floors, up to about a metre high, and may indicate a failed damp-proof course
Penetrating damp: water coming through walls, often near windows, rooflines, or external defects
Condensation: moisture from inside the property, often worse in bathrooms, kitchens, and poorly ventilated bedrooms
If the cause isn't obvious, commission a damp survey. Don't guess.
Property history
Has this issue been reported before?
Have similar problems occurred at neighbouring properties or other units in the same building?
Is there a pattern suggesting a systemic issue?
Communicating with the Tenant
Good communication can turn a frustrated tenant into a cooperative one. Poor communication turns a minor issue into a formal complaint.
Keep them informed at every stage. Don't wait for them to chase. Proactive updates — even just "we're still waiting on the contractor to confirm availability" — show you're on it.
Don't promise timelines you can't keep. If you're not sure when the repair will happen, say so. "We're aiming for next week but I'll confirm once the contractor responds" is better than "it'll be done by Friday" followed by silence.
If temporary measures are needed, arrange them. Dehumidifiers, mould wash, improved ventilation advice — these aren't solutions, but they show good faith and may prevent the problem from worsening while you address the root cause.
Document every conversation. If you speak to the tenant by phone, follow up with a brief email summarising what was discussed. This protects you both.
After the Repair
The job isn't finished when the contractor leaves.
Check back with the tenant after 4–6 weeks. Government guidance recommends this. Has the mould returned? Is the tenant satisfied? If the problem recurs, you need to investigate again — don't assume the original fix worked.
If mould returns, don't just repeat the same repair. Recurring mould suggests the root cause wasn't addressed. You may need a more thorough survey, a different approach, or works to the building fabric rather than surface treatment.
Consider whether other properties might be affected. If the cause is structural — a design flaw, poor insulation, inadequate ventilation — it may affect neighbouring units or similar properties in your portfolio. Proactive checks now can prevent a wave of complaints later.
When to Involve the Landlord
If you're a managing agent, the landlord needs to be in the loop — especially if significant spend is required.
Get approval early for major works. Don't wait until the last minute. If a damp-proof course needs replacing or the roof needs attention, flag it as soon as you know.
Keep landlords informed of risk. A damp complaint that escalates to a Housing Ombudsman investigation or a disrepair claim is the landlord's liability, not just yours. Make sure they understand the stakes.
Document landlord instructions. If a landlord refuses to authorise necessary works, record that in writing. You may need to demonstrate later that you recommended action and were overruled.
The Bottom Line
Damp and mould complaints aren't going away. With increased regulatory scrutiny, rising tenant awareness, and the expansion of Awaab's Law principles to the private sector, the bar for how you respond is higher than ever.
But the fundamentals haven't changed: respond quickly, investigate properly, communicate clearly, and document everything. Do those four things consistently, and most cases will resolve without drama.
Ignore them, and you'll keep learning the hard way.
Lanten helps letting agents handle damp and mould reports properly — triaging issues automatically, collecting the right information upfront, and logging every step for compliance. Book a demo to see how it works.
