Mould in a rented flat rarely stalls because nobody has noticed it. It stalls over one question: whose job is it. The tenant says the flat is cold and the bathroom fan does nothing. The landlord or agent says the windows are never opened and the washing is dried indoors. Months pass, the patch spreads, and nobody has measured anything.
This guide sets out who does what, how to report mould so the report counts, what a landlord in England is generally responsible for, what Awaab's Law changed, and how an independent survey of the water source fits in. It is general information, not legal advice. For your own situation, speak to Shelter, Citizens Advice or your council's environmental health team.
Who is responsible for mould in a rented flat?
The short version, which holds in most cases: the tenant reports the problem in writing to the landlord or managing agent, and the landlord arranges the investigation and any repair. A tenant does not normally commission a survey of a property they do not own, and a landlord who has not been told is usually not on the hook yet.
That division matters practically as much as legally. The freeholder, the flat above and the building's pipework are all things a landlord or agent can reach and a tenant often cannot. If the water is coming from the flat above or a communal riser, only the landlord or managing agent can realistically get it looked at.
Where the flat is one of several in a converted house or a block, a third party may be involved: the freeholder or the block's managing agent, who looks after the structure and communal services. A leak from a riser or a roof is their problem rather than the landlord's, and the landlord has to take it up with them.
How should you report mould to a landlord or agent?
In writing, and keep a copy. A phone call leaves no record, and a written record is what makes the difference later if the problem is not dealt with.
- Email rather than call, or follow a call up with an email saying what you discussed and when.
- Say where it is and how big it is. Which room, which wall, roughly what size, and whether it is spreading.
- Attach dated photographs, and take fresh ones every couple of weeks.
- Say when it is worst. After rain, in cold weather, when the heating runs, after someone showers. Each points at a different cause.
- Mention anything that is not working, such as a dead extractor fan, windows that will not open, a cold radiator or a leak from the flat above. Say too if anyone in the household has asthma or another respiratory condition.
Shelter's guidance makes the same point: reporting in writing creates a written record of when and how the problem was raised, which is the evidence that matters if the landlord does not act.
What is a landlord generally responsible for in England?
Two pieces of law do most of the work, and both sit inside the Landlord and Tenant Act 1985.
| What it is | What it broadly covers | How it applies to mould |
|---|---|---|
| Section 11, Landlord and Tenant Act 1985 | Keeping the structure and exterior in repair, and the installations for water, gas, electricity, sanitation, space heating and hot water | Where the damp comes from disrepair, such as a roof leak, a failed gutter or a leaking pipe, the repair is generally the landlord's |
| Homes (Fitness for Human Habitation) Act 2018 | Amended the 1985 Act so private and social landlords must keep a home fit for human habitation at the start of and throughout the tenancy | Freedom from damp is one of the matters considered, so a home made unsuitable for occupation by damp and mould can be unfit even without disrepair |
| Awaab's Law | Timescales for investigating hazards and making them safe, in force for social landlords from 27 October 2025 | Significant damp and mould must be investigated within 10 working days and made safe within a further 5 working days |
| Your tenancy agreement | Anything the agreement adds, such as who maintains an extractor fan | A term cannot be used to sign away the section 11 repairing obligations |
The point worth holding on to is that the fitness duty is wider than the repair duty. A wall can be in perfect repair and the home still be damp because of the way it is built, heated or ventilated.
Does it matter whether the mould is condensation or a leak?
It matters for what gets fixed, and it is the point most disputes turn on, because condensation is the one cause that gets blamed on the household.
Government guidance for rented housing providers is direct about this. It says it is unreasonable to blame damp and mould on lifestyle choices, because everyday tasks such as cooking, bathing, washing and drying laundry unavoidably produce moisture indoors, and it identifies the fundamental causes as building deficiencies, inadequate ventilation, inadequate heating or poor energy efficiency.
Shelter's guidance makes a related point: a landlord should not assume damp and mould is a lifestyle problem where there are design or structural issues, and condensation can be the landlord's responsibility where the design prevents proper ventilation, or where it is damaging the structure or creating a health and safety risk.
Where it is a leak, the argument tends to end quickly, because a leak is disrepair and disrepair is squarely the landlord's. Our guide to mould on a wall, leak or condensation explains how the two are told apart.
What is Awaab's Law and does it apply to a private flat?
Awaab's Law is named after Awaab Ishak, a two year old who died after prolonged exposure to mould in a social home. The first phase came into force on 27 October 2025 and applies to social landlords. It sets fixed timescales: emergency hazards must be investigated and made safe within 24 hours of the landlord being made aware, and significant damp and mould hazards must be investigated within 10 working days, with the property made safe within a further 5 working days. The duties are due to extend to more hazards in social housing from October 2026 and again in 2027.
For private tenants, the Renters' Rights Act creates the power to extend Awaab's Law to privately rented homes by implying similar terms into tenancy agreements, with the detail and timescales to be set out in regulations after consultation. A private tenant should not assume the social housing timescales apply today. Section 11 and the fitness for habitation duty do apply to private tenancies now.
What evidence helps?
Evidence moves a mould complaint from an argument about habits to a decision about a building.
- Dated photographs of each patch, taken repeatedly so that spread is visible.
- The written reports, with dates, and every reply from the landlord or agent.
- A record of conditions: when the mould is worst, whether it follows rain, and whether the extractor fan works.
- Medical evidence where health is affected, such as a GP record, which Shelter lists among the evidence supporting a disrepair case.
- An independent survey with readings: environmental conditions, surface temperatures, moisture readings across the affected area, and a conclusion on where the water is coming from.
- Council involvement. A council's environmental health team can inspect a private rented home and assess hazards, including damp and mould.
How does a leak detection report fit in?
A leak detection or damp survey answers a narrow question well: is water escaping into this structure, and if so, from where. That is usually the question a stalled mould dispute needs answered.
If the survey finds a leak, the report names the pipe or fitting, shows the readings that led there, and gives the landlord something a plumber can act on. If it finds no leak, the report says so and sets out what the readings do show: a cold wall, a surface falling below the dew point, a dead extractor fan, a cold bridge at a lintel, a failed gutter soaking an external wall. Either result beats another visit where somebody looks at the wall and forms an opinion.
In practice the survey is normally arranged and paid for by the landlord or the managing agent, because they own the building and control access. A tenant who wants one usually asks the landlord to instruct it. Our guide to leak detection responsibility for landlords covers that side, and what a leak detection report should contain sets out what a useful report looks like.
What if the landlord does not act?
Keep reporting in writing, and keep the record. Beyond that, the usual routes in England are the landlord's or agent's complaints procedure, the council's environmental health team, which can inspect and require action on hazards in private rented homes, and, for social tenants, the Housing Ombudsman. Shelter and Citizens Advice publish step by step guidance, and legal advice is worth taking before a disrepair claim.
We can help with the technical half: establishing whether there is a water source, and documenting it. We cannot advise on tenancy law or on what action to take against a landlord.
When should a specialist be called?
A survey earns its place when the mould keeps returning after cleaning, when it sits on an internal wall or next to a pipe run, when the plaster is blown, when there is a stain on a ceiling under another flat, or when landlord and tenant disagree about the cause and need something measured.
The limits are worth stating. We find and document the water source. We do not take laboratory or air samples, we do not count spores, we do not carry out mould removal, and we do not issue mould clearance certificates. Cleaning and redecoration are a separate job, and where the cause is a building defect or ventilation the work belongs to a builder, roofer or ventilation installer.
Our damp and mould survey is £250 to £450. Where a leak needs tracing and confirming, a combined detection package is £250 to £500 and a trace and access survey is £350 to £450. Call 020 3912 0200 to talk it through.
Frequently asked questions
Is mould in a rented flat the landlord's responsibility?
Generally the landlord is responsible where the damp comes from disrepair, such as a leak or a structural defect, and where the home is not fit for human habitation. Condensation can also be the landlord's responsibility where the design, ventilation or heating is the underlying cause. This is general information, not legal advice.
Should I report mould by phone or in writing?
In writing, and keep a copy. A written report creates a dated record of when and how the problem was raised, which is the evidence that counts later.
Can a landlord blame mould on my lifestyle?
Government guidance for rented housing providers says it is unreasonable to blame damp and mould on lifestyle choices, because cooking, bathing, washing and drying laundry unavoidably produce moisture. It points to building deficiencies, ventilation, heating and energy efficiency as the fundamental causes.
Does Awaab's Law cover private rented flats?
The first phase, in force since 27 October 2025, applies to social landlords. The Renters' Rights Act creates the power to extend it to privately rented homes, with the detail and timing to be set out in regulations after consultation.
Who pays for a mould or damp survey in a rented flat?
It is normally arranged and paid for by the landlord or managing agent, since they own the building and control access to the rest of it. A tenant who wants one usually asks the landlord to instruct it.
Can you remove the mould once you have found the cause?
No. We find and document the water source and set out what is making the wall wet. Cleaning, redecoration and any building or ventilation work are carried out by other trades.
