Mould in Rental Properties: Landlord and Tenant Responsibilities in Australia (2026)

Mould is one of the most common causes of disputes between landlords and tenants in Australia — and one of the most consistently misunderstood. Every year, thousands of tenancy matters involve mould: who caused it, who is responsible for fixing it, and who pays when it damages walls, carpets, or belongings.

Australia's climate does not help. Humid summers across Queensland and coastal New South Wales, cold wet winters in Melbourne and Canberra, and condensation-prone housing stock create conditions where mould establishes quickly. Many older rental properties were built without ventilation standards suited to modern occupancy patterns. Tenants cooking, showering, drying laundry indoors, and running heaters in poorly ventilated homes will generate moist air. Properties with leaking pipes, faulty weatherproofing, or inadequate exhaust systems will trap that moisture.

The dispute arises because mould can have two distinct origins in the same property. Structural mould — caused by leaks, rising damp, condensation from poorly insulated walls, or inadequate weatherproofing — is the landlord's responsibility. Lifestyle mould — caused by insufficient ventilation during bathing, cooking, or indoor laundry drying — is typically the tenant's responsibility. Often, a single mould problem involves both. Sorting out which is which is where most disputes live.

Recent minimum standards reforms in most states have clarified the landlord's baseline obligations, but they have not eliminated disputes. What they have done is raise the floor: a landlord can no longer simply blame a tenant for mould that is visibly caused by a structural defect. Knowing these standards — and documenting property condition accurately at entry and exit — is now a core competency for property managers across Australia.

In every Australian state and territory, the landlord's core obligation is the same: the property must be fit for habitation and maintained in good repair throughout the tenancy. Mould caused by structural defects — leaking roofs or pipes, rising damp, condensation from inadequate insulation, faulty exhaust systems, or poor weatherproofing — falls squarely within the landlord's responsibility.

When a tenant reports mould and provides a plausible explanation linking it to a structural issue, the landlord (or their property manager) must investigate promptly. Ignoring the report, or simply asking the tenant to clean the mould without identifying the source, is not adequate. If the mould returns after cleaning, that is strong evidence of a structural cause and shifts the burden back to the landlord to address the root issue.

Several states have now made the mould obligation explicit through minimum property standards:

Victoria — Consumer Affairs Victoria's minimum standards (effective March 2021) include that the rental property must be free from mould and damp caused by or related to the building structure.

Queensland — Under the minimum housing standards introduced via the Housing Legislation Amendment Act 2021 (Qld), effective for new tenancies from September 2023 and for all tenancies from September 2024, properties must not have any significant mould or damp caused by or related to the building structure.

Western Australia — Minimum standards under the Residential Tenancies (Minimum Standards) Regulations 2022, effective July 2023, require premises to be weatherproof and structurally sound — directly covering mould caused by water ingress.

Even in states without an explicit mould minimum standard, the general obligation to maintain the property in good repair covers structural mould.

Practically, a landlord who receives a written mould complaint and fails to investigate within a reasonable timeframe is exposed to: a compensation claim from the tenant for damage to belongings; a tribunal order requiring repairs and potentially compensation; and a reduction in or loss of bond if the mould worsened during the tenancy due to the landlord's failure to act. Property managers should document all mould reports with dates, descriptions, and photos, and keep records of all maintenance work completed in response.

Tenants are not passive participants in mould prevention. Under the general obligation to keep the property clean and in good condition, tenants are expected to ventilate adequately — particularly during activities that generate moisture: cooking, showering, bathing, and drying laundry indoors.

In practice this means:

• Using rangehood fans and bathroom exhaust fans when cooking and showering
• Opening windows in kitchens and bathrooms after use where ventilation fans are absent or insufficient
• Avoiding drying large quantities of laundry in poorly ventilated rooms
• Reporting any structural issues — leaks, broken exhaust fans, signs of damp — to the property manager promptly
• Cleaning surface mould in kitchens, bathrooms, and other moisture-prone areas as part of routine maintenance

When mould in a rental is caused primarily by tenant behaviour — for example, a bathroom with a functional exhaust fan where the tenant routinely showers without using it — the remediation cost can properly be attributed to the tenant. This may form the basis of a bond claim at exit if the mould has damaged tiles, grout, paint, or ceiling surfaces.

However, tenants are not responsible for mould they have no practical means to prevent. If the exhaust fan was broken at entry and the property manager did not fix it despite being notified, the tenant is not responsible for resulting mould. If the bathroom walls have no insulation and condensation is inevitable regardless of ventilation habits, the tenant is not responsible for the damp.

The entry condition report is critical here. A well-completed report that documents the state of exhaust fans, any visible mould, and the condition of walls and ceilings at the start of the tenancy creates the baseline that makes it possible to determine what changed during the tenancy and why.

The practical challenge is that mould itself does not announce its cause. A black patch on a bathroom ceiling could result from poor tenant ventilation, an inadequately waterproofed roof, or a combination of both. Signs that point toward structural (landlord) causes:

• Mould appearing in rooms not typically associated with moisture generation — bedroom walls, under-sink cupboards, living room corners near external walls
• Mould at locations where water ingress is plausible — around window frames, at wall-ceiling junctions on external walls, near pipe penetrations
• Mould returning consistently in the same location shortly after cleaning
• Visible water damage (discolouration, bubbling paint, efflorescence) adjacent to the mould
• Mould establishing in a new tenancy within a few weeks of move-in, before lifestyle habits could reasonably be blamed

Signs that point toward lifestyle (tenant) causes:

• Mould concentrated in bathrooms, kitchen, or laundry — moisture-generating areas — with functional exhaust present
• Evidence that exhaust fans are not being used (grease or dust build-up on fan covers, no discolouration patterns consistent with use)
• Large volumes of indoor laundry documented in inspection photos
• Condensation on windows throughout the property, indicating high interior humidity
• Mould in areas of poor airflow adjacent to moisture-generating activities

In contested cases, a mix of contributing factors is common. A property manager reporting to the landlord should describe both the evidence of structural condition and any tenant behaviour observed, without pre-judging liability. Where the root cause is genuinely unclear, engaging a licensed building inspector or a mould remediation professional to assess and provide a written report is appropriate — and their report can be used at tribunal if needed.

The landlord's general obligation to maintain a property in good repair applies in every jurisdiction. Several states have gone further with explicit minimum standards. Here is a concise summary for each jurisdiction as at May 2026:

New South Wales — No mould-specific minimum standard under NSW Fair Trading's current guidance, but the Residential Tenancies Act 2010 (NSW) requires that a landlord provide and maintain the property in a reasonable state of repair. A property with structural damp or mould caused by a building defect does not meet this obligation. NSW Fair Trading handles disputes informally; unresolved matters proceed to the NSW Civil and Administrative Tribunal (NCAT).

Victoria — Consumer Affairs Victoria's minimum standards (Residential Tenancies Regulations 2021) explicitly require that the rental property be free from mould and damp caused by or related to the building structure. These standards apply to all tenancies. Disputes proceed to the Victorian Civil and Administrative Tribunal (VCAT). See also Victoria's minimum standards checklist.

Queensland — Minimum housing standards under the Residential Tenancies and Rooming Accommodation Act 2008 (Qld), as amended, require that premises not have any significant mould or damp caused by or related to the building structure. These standards apply to all tenancies from September 2024. The RTA Queensland provides a dispute resolution process; unresolved matters proceed to the Queensland Civil and Administrative Tribunal (QCAT).

Western Australia — Minimum standards under the Residential Tenancies (Minimum Standards) Regulations 2022 require that premises be weatherproof and structurally sound. Mould caused by water ingress or structural deficiency is covered. Consumer Protection WA handles complaints; disputes proceed to the Magistrates Court. See WA bond condition report rules for related detail.

South Australia — The Residential Tenancies Act 1995 (SA) places a general maintenance and repair obligation on landlords. There is no explicit mould standard, but structural mould falls within the repair obligation. Consumer and Business Services SA (CBS) handles tenancy complaints; disputes proceed to the South Australian Civil and Administrative Tribunal (SACAT). See SA condition report requirements.

Tasmania — Minimum standards under the Residential Tenancy Act 1997 (Tas), as amended from October 2022, include that premises must be weatherproof and in good repair. Mould from water ingress falls within this standard. Consumer, Building and Occupational Services (CBOS) Tasmania provides guidance; disputes proceed to the Residential Tenancy Commissioner or Magistrates Court.

Australian Capital Territory — The Residential Tenancies Act 1997 (ACT) and Residential Tenancies (Residential Standards) Declaration apply. Standards include that premises must be structurally sound and weatherproof. Access Canberra handles tenancy matters; disputes proceed to the ACT Civil and Administrative Tribunal (ACAT).

Northern Territory — The Residential Tenancies Act 1999 (NT) applies. NT Consumer Affairs provides guidance. There is no explicit mould minimum standard, but the general repair obligation covers structural causes. Disputes proceed to the Northern Territory Civil and Administrative Tribunal (NTCAT).

An entry condition report that does not properly document existing mould is a liability for both the landlord and the property manager. If mould is present at entry and goes unrecorded, the landlord may be unable to defend against a claim that it was their responsibility to fix — and equally unable to attribute it to tenant behaviour at exit, because there is no baseline showing the mould was present before the tenancy started.

For each area where mould is present or where mould is likely (bathrooms, laundry, kitchen, external-facing walls, under-sink cupboards), the entry condition report should note:

• Whether mould is visible and, if so, its location, approximate extent, and colour
• The condition of exhaust fans — functional, non-functional, or absent
• The condition of seals around baths, shower recesses, and vanity basins (failed silicone is a frequent contributor)
• Any visible water staining, damp patches, or bubbling paint that may indicate moisture ingress
• The ventilation arrangements for each moisture-generating area

Photographs should support each notation. A close-up of a ceiling mould patch in the bathroom, combined with a note that reads "minor mould on ceiling tiles, approximately 20 cm × 15 cm, adjacent to shower recess — exhaust fan present and operational," creates a clear, defensible baseline.

If significant structural mould is present at entry, the appropriate action is usually to arrange remediation before the tenancy commences rather than noting it on the report and handing the property over. An entry condition report that documents extensive mould is evidence of a property that did not meet minimum standards at tenancy commencement — a meaningful liability for the landlord.

Property managers completing entry condition reports should treat the mould documentation with the same rigour as damage documentation. Vague entries like "bathroom — some marks on ceiling" will not withstand scrutiny at tribunal. Specific entries like "bathroom ceiling — black mould patch, approx. 25 cm × 20 cm, directly above shower, exhaust fan functional" will.

When mould is identified during a routine inspection, the property manager has a clear set of obligations. Ignoring it or noting it without follow-up creates risk for both the landlord and the agency.

1. Document thoroughly. Photograph the mould with reference to the location, and note it in the inspection report with a description of its extent. Note any associated symptoms — water staining, damp surfaces, failed sealing around fixtures.

2. Assess the likely cause. Is this in a moisture-generating area with functional exhaust present? Is it on an external wall or in a room not associated with moisture? The first assessment informs the likely responsible party and the appropriate response.

3. Notify the landlord. Routine inspection reports should be shared with the landlord. Mould findings should be flagged as requiring a decision: engage a tradesperson to investigate the structural question, issue the tenant with a ventilation reminder, or both.

4. Issue written instructions to the tenant where appropriate. If tenant behaviour appears to be a contributing factor, issue a written reminder about ventilation practices and the condition of exhaust fans as part of the routine inspection follow-up communication. This creates a paper trail directly relevant to any future bond claim — and signals to the tenant that the issue has been noted.

5. Follow up at the next inspection. Check whether the mould has been remediated, recurred, or spread. A mould problem that persists or worsens despite landlord action points toward a structural cause. A problem that resolves after a tenant behaviour reminder points toward a lifestyle cause. A pattern of recurring mould in the same location is something a tribunal will take seriously.

Property managers who fail to document mould at a routine inspection and then attempt a bond claim for mould damage at exit face a significant evidentiary gap: there is no inspection record showing when the mould appeared or what steps were taken. The routine inspection record is part of the evidence chain, not a separate exercise.

At exit, the condition report should document the state of every area that had noted mould on the entry report, as well as any new mould that has appeared during the tenancy. The comparison between entry and exit reports — combined with routine inspection records and any written communications — determines whether a bond claim for mould-related damage is viable.

For a bond claim relating to mould to succeed:

• The entry condition report must show the affected area was free from mould at the start of the tenancy, or that the mould was minor and has significantly worsened
• The exit condition report must clearly document the extent and location of the mould at exit
• The mould must be attributable to tenant behaviour rather than a structural defect that the landlord failed to address
• The damage must exceed fair wear and tear — surface mould that cleans off easily is unlikely to be awarded; mould that has stained tiles, grout, or ceiling paint and requires professional remediation may be

See fair wear and tear vs damage for the general framework tribunals apply when assessing what constitutes damage beyond fair wear and tear.

Tribunals in all states take a consistent approach: if the landlord cannot demonstrate that the mould was absent at entry and was caused by tenant behaviour rather than a structural issue, the claim will not succeed. This is why thorough entry and exit reports — with specific written descriptions and supporting photographs — are essential.

Where the amount in dispute is significant, engaging a licensed mould remediation professional to inspect and provide a written report before the exit inspection, and an estimate or invoice after, will substantially strengthen the claim. A professional assessment that attributes the mould to poor ventilation habits rather than structural cause is far more persuasive at tribunal than a property manager's opinion alone.

For a broader overview of building the evidence required for successful bond claims, see winning bond disputes guide.

In severe cases, mould in a rental property goes beyond a condition report or bond question and becomes a health and safety matter. Extensive mould growth can cause or exacerbate respiratory conditions, particularly in occupants with asthma, allergies, or compromised immune systems. When a tenant raises health concerns related to mould, property managers should treat the matter with urgency — not primarily for liability reasons, but because the obligation to provide safe and habitable premises is a genuine one.

Signs that a mould problem may have reached health-significance:

• Mould covering large surface areas across multiple rooms
• Mould growing inside air conditioning units or ducting (which distributes spores throughout the property)
• Black mould (Stachybotrys chartarum) in areas of persistent damp — while all mould should be addressed, this species is associated with more significant health effects
• A tenant reporting health symptoms they attribute to the mould

In these circumstances, the appropriate response is to engage a licensed mould assessor or building professional to inspect, identify the source, and recommend remediation — not to ask the tenant to clean the mould themselves or to delay action until the next scheduled inspection.

In some states, severe housing disrepair that threatens health can be reported to the local council, which has powers under public health legislation to issue orders to the landlord. NSW Fair Trading, Consumer Affairs VIC, RTA Queensland, and equivalent bodies in other states can also be contacted for advice where a landlord is unresponsive.

Property managers have a duty of care that sits alongside their obligation to the landlord client. Where a property presents a genuine health risk, the property manager's responsibility is to ensure the landlord takes action — and to document their advice clearly if the landlord declines.

Most mould disputes at VCAT, NCAT, QCAT, ACAT, and equivalent tribunals come down to three questions:

1. Was the property structurally sound and free from mould at the start of the tenancy? If a landlord let a property with pre-existing mould that should have been remediated, the tenant can apply for rent reductions or compensation, and any bond claim for mould damage at exit is likely to fail. The entry condition report and any pre-tenancy photographs are the primary evidence on this question.

2. Did the landlord respond reasonably to mould complaints? If a tenant reported mould in writing and the landlord delayed, ignored the report, or failed to investigate the structural cause, this weighs heavily against the landlord. The record of maintenance requests and the property manager's responses to them is examined closely.

3. Did the tenant take reasonable steps to prevent and report mould? If a tenant says nothing about visible mould for eighteen months and then claims it is entirely the landlord's responsibility, this weighs against the tenant. Tenants have both a reporting obligation and a ventilation obligation. Routine inspection reports that include written reminders to the tenant about ventilation are useful evidence here.

The evidence that determines outcomes is almost always documentary: entry and exit condition reports, routine inspection reports, maintenance request records, and written communication between the parties. Property managers who maintain complete, timestamped documentation across the full tenancy will consistently achieve better outcomes than those who rely on memory or incomplete records.

A common outcome in contested cases is a shared cost order — the tribunal determines that both parties contributed to the mould problem and apportions the remediation cost accordingly. Property managers who can show they issued written ventilation reminders, responded to maintenance reports promptly, and documented the property's condition at every stage are more likely to achieve a favourable apportionment.

For practical guidance on building a complete evidence record for bond disputes more broadly, see condition report mistakes that sink bond claims and how to photograph rental damage for bond evidence.

Can a landlord refuse to fix structural mould? No. A landlord cannot lawfully refuse to address mould caused by a structural defect. Doing so exposes them to a tribunal order requiring repairs, a compensation claim from the tenant for damage to belongings or health impacts, and potential penalties under state tenancy legislation. A landlord can dispute responsibility for mould they believe is caused by tenant behaviour, but they must investigate rather than simply decline to act.

Can a tenant withhold rent over mould? Tenants cannot unilaterally withhold rent in any Australian state. If the property has a significant mould problem the landlord is refusing to address, the correct process is to apply to the relevant tribunal — NCAT (NSW), VCAT (VIC), QCAT (QLD), SACAT (SA), Magistrates Court (WA), ACAT (ACT), NTCAT (NT), or the Residential Tenancy Commissioner (TAS) — for an urgent order or rent reduction. Withholding rent exposes the tenant to a breach notice and potential termination of the tenancy.

How quickly must a landlord fix reported mould? Timeframes vary by state and by the severity of the problem. Where mould is causing a health risk or renders part of the property uninhabitable, some states treat this as an urgent repair requiring a faster response. For non-urgent structural mould, the "reasonable time" standard generally means investigation and diagnosis within two to four weeks of a written report, with remediation works following within a reasonable period after that. Property managers should confirm current urgent repair definitions with the relevant state authority.

Can the bond be claimed for mould cleaning? Yes, where the mould is demonstrably caused by tenant behaviour (poor ventilation, failure to clean) rather than a structural issue, and where the extent exceeds normal wear and tear. Surface mould that wipes off easily is unlikely to be awarded. Mould that has stained tiles, grout, or ceiling paint and requires professional remediation, and which can be attributed to tenant behaviour based on entry/exit comparison and inspection records, is more likely to succeed as a claim.

Who is responsible if the exhaust fan breaks during the tenancy? The exhaust fan is a landlord's responsibility to maintain and repair. If the tenant reports a broken exhaust fan and the landlord fails to fix it, the landlord bears responsibility for mould that develops as a direct result. If the exhaust fan breaks, the tenant does not report it, and mould develops, responsibility is more likely to be shared — the landlord for the delay in discovering and fixing the fault, the tenant for failing to report a known defect.

Does taking photos of mould at the routine inspection help? Yes, significantly. Routine inspection photos of mould establish a timeline: when the mould first appeared, whether it was minor or extensive, and whether the property manager issued instructions. This timeline is central to determining cause and responsibility at dispute time. Document mould at every routine inspection with the same specificity you would use in a condition report.