The Legal Framework: What NSW Law Actually Says About Mould
Mould in NSW rental properties sits at the intersection of multiple legal frameworks: the Residential Tenancies Act 2010, the standard residential tenancy agreement, the Residential Tenancies Regulation 2019, and in some cases, the Environmental Planning and Assessment Act for short-term rentals.
For residential landlords in Northern Rivers NSW — managing properties in Byron Bay, Ballina, Lismore, Bangalow, Mullumbimby, Murwillumbah, and Casino — understanding these obligations is not optional. NSW Fair Trading enforces tenancy standards, and the NSW Civil and Administrative Tribunal (NCAT) has consistently upheld tenants’ rights to habitable premises, including the right to mould-free conditions where the mould is the building’s problem rather than the tenant’s behaviour.
This guide explains what the law requires, what landlords must do and when, and what the consequences of non-compliance are.
The Core Legal Obligation: Fit for Habitation
Section 52 of the Residential Tenancies Act 2010
The fundamental obligation is in section 52 of the Residential Tenancies Act 2010 (NSW): a landlord must provide and maintain residential premises in a condition reasonably fit for habitation.
This is not a subjective standard. A tribunal will assess whether the condition of the premises — including any mould present — makes the property unsuitable for a reasonable occupant to live in.
Relevant factors include:
- The extent and location of mould
- The health effects mould exposure is causing or is reasonably likely to cause
- Whether the mould prevents the reasonable use of any part of the premises
- The cause of the mould and who is responsible for that cause
Section 63: Landlord’s Obligation to Repair
Under section 63 of the Residential Tenancies Act, a landlord must maintain the premises in a reasonable state of repair, having regard to the condition of the premises at the start of the tenancy.
Mould that is caused by or exacerbated by a defect in the building — inadequate ventilation, moisture ingress through a structural defect, plumbing failure — is a repair obligation. The landlord must address both the defect and the resulting mould.
The 2023 Amendments: Rental Reforms
The Residential Tenancies Amendment Act 2023 introduced significant strengthening of renter protections in NSW, including around property condition standards. These amendments reinforce the obligation to maintain habitable premises and provide tenants with clearer pathways to enforce those obligations through NCAT.
Who Is Responsible for Mould: Landlord or Tenant?
This is the most contested question in mould-related tenancy disputes.
Landlord’s Responsibility
The landlord is responsible for mould where:
The mould is caused by the building’s condition. Inadequate ventilation systems, structural moisture ingress, roof leaks, rising damp, plumbing defects — these are building issues that the landlord must address. Mould resulting from these conditions is the landlord’s responsibility regardless of how long the tenant has been in the property.
The mould existed at the commencement of the tenancy. A landlord who lets a property with existing mould is in breach of the Section 52 obligation from day one.
The mould is the result of a flood or stormwater event. In Northern Rivers properties affected by flooding or storm damage — including the 2022 Lismore flood impacts — any mould resulting from that event is the landlord’s responsibility to remediate.
The mould was reported and not addressed. A tenant who reports mould and does not receive a response within a reasonable timeframe has grounds to apply to NCAT for a maintenance order. The landlord’s failure to respond does not transfer the responsibility — it creates additional liability.
Tenant’s Responsibility
A tenant may bear responsibility for mould where:
- The tenant has caused the mould through their own actions — for example, failing to use exhaust fans, consistently drying clothes indoors without ventilation in an otherwise well-ventilated property, or blocking ventilation openings
- The mould is in a space exclusively under the tenant’s control where the building’s ventilation is adequate for normal use
The practical reality: In Northern Rivers NSW, where ambient humidity is extremely high during the wet season and many properties have older, less effective ventilation systems, attributing mould to tenant behaviour is very difficult to sustain in a tribunal. NCAT is generally sceptical of landlords who blame tenant behaviour for mould in coastal or subtropical properties without strong evidence.
Response Time Requirements
The Residential Tenancies Act and Regulation distinguish between urgent and non-urgent repairs:
Urgent Repairs
Mould that poses a health risk to tenants may constitute an urgent repair under section 62 of the Act. The list of urgent repairs in the Act includes serious damage to the premises and any defect that makes the premises unsafe or insecure.
Where a tenant has reported mould and there is evidence of health effects (respiratory symptoms, medical advice to vacate, visible extensive mould in a regularly used area), a landlord should treat this as urgent and respond within 24 to 48 hours.
Non-Urgent Repairs
For mould that is present but not causing immediate health risk, the landlord should respond within 14 days of notification. However, this should not be interpreted as a 14-day deadline before which a landlord can ignore a mould report. The obligation is to act reasonably, and unreasonable delay can result in a NCAT order.
Practical recommendation: For any mould report, arrange professional assessment within 7 days. This demonstrates good faith and provides objective information about the seriousness of the issue.
What “Addressing Mould” Actually Means
A landlord’s response to a mould report must be appropriate to the nature of the mould. The following responses are NOT considered adequate:
- Sending the property manager to clean the mould with a bleach spray
- Repainting over the mould without treating it
- Telling the tenant to ventilate better without addressing structural ventilation deficiencies
- Waiting to see if the mould “goes away” as the wet season ends
An appropriate response includes:
- Professional assessment to identify the cause and extent of the mould
- Treatment appropriate to the severity — surface treatment for surface mould, full remediation for structural mould
- Addressing the underlying moisture source (otherwise the mould will recur)
- Written documentation of the assessment and treatment provided to the tenant
The Consequences of Non-Compliance
NCAT Maintenance Orders
A tenant can apply to NCAT for a maintenance order requiring the landlord to carry out repairs. If NCAT grants the order, the landlord must carry out the specified work within the timeframe the Tribunal sets. Failure to comply is a breach of the Tribunal order — a serious legal matter.
Rent Reduction Orders
NCAT can order a reduction in rent for the period during which the premises were not in a condition reasonably fit for habitation. This reduction can be backdated to when the tenant first reported the mould problem.
Compensation Orders
Where a tenant has suffered loss — medical costs, replacement of personal belongings damaged by mould, costs of temporary alternative accommodation — NCAT can order the landlord to pay compensation.
Termination in Extreme Cases
In cases of severe mould making premises uninhabitable and a landlord who refuses to act, NCAT has the power to terminate the tenancy and release the tenant from their obligations without penalty.
Practical Steps for Northern Rivers Landlords
At lease commencement: Inspect for mould before the tenant moves in. Remediate any mould present. Document the condition with photographs and provide a copy to the tenant in the ingoing inspection report.
When a mould report is received: Acknowledge the report in writing within 24 hours. Arrange a professional assessment within 7 days. Provide the tenant with the assessment findings and the planned treatment timeline.
After treatment: Obtain a completion report from the treating technician. Provide a copy to the tenant. Keep a copy for your records.
Preventive approach: In the Northern Rivers humid climate, a proactive annual inspection and maintenance fogging programme is far cheaper than the NCAT and remediation costs of mould disputes.
Frequently Asked Questions
My tenant is blaming the mould on their lifestyle (drying clothes inside, not using exhaust fans). Do I still have to remediate? If the building’s ventilation is adequate for normal residential use and the mould is genuinely caused by tenant behaviour, you may have grounds to argue the tenant is responsible. You need professional assessment evidence to support this — not just your assertion. If the ventilation is genuinely inadequate for the property’s climate and use (which is very common in older Northern Rivers homes), NCAT is likely to find the landlord responsible regardless of tenant behaviour.
The mould came back six months after I had it treated. Does that mean the treatment didn’t work, and am I liable again? Mould recurrence after treatment usually indicates that the underlying moisture source was not fully resolved — or that the original treatment was surface-only and did not address structural mould. If the mould has recurred and the tenant reports it, your obligation to address it is refreshed. Repeated mould in the same location is strong evidence of a structural issue that requires proper remediation, not repeated surface treatment.
Can I pass the cost of mould remediation to the bond? No, unless you can clearly establish that the mould is the result of the tenant’s deliberate or negligent actions and not the building’s condition. Mould caused by the building’s inadequate ventilation or structural deficiencies cannot be charged to the tenant bond.
Do I need a professional mould inspection or can I just arrange for cleaning? You need a professional assessment for any mould complaint that involves more than a trivial, clearly surface-level patch in an obviously adequate location. The assessment establishes the cause, extent, and required treatment — and provides the documentation you need for your records in the event of a dispute.
We Help Northern Rivers Landlords
We work with landlords across Byron Bay, Ballina, Lismore, Lennox Head, Bangalow, Mullumbimby, Murwillumbah, and Casino to provide professional mould assessment reports and remediation services. Our reports meet the documentation standard required by NCAT and insurance companies.
Request a Free Quote — assessment appointments typically available within 24 hours.