Reviewed and updated 9 October 2026 by Nick Roth, Mould Remediation Specialist, AllAces Cleaning & Restoration
In NSW, the landlord usually pays when mould comes from the building: a leak, rising damp, a failed shower membrane or a room with no real ventilation. The tenant usually pays when it comes from how the home is used and they didn’t report it. NSW law never actually says the word “mould”, though.
So every case of mould in a NSW rental comes back to one question: where is the damp coming from? This guide covers what the law says, how to tell a building fault from a lifestyle one, and what to do next, whether you rent the place or own it.
It applies across NSW, from Sydney apartments to the Central Coast and the North Coast.
General information, not legal advice. For your own situation, talk to a Tenants’ Advice and Advocacy Service or a lawyer.
Key takeaways
- No mould rule, but a damp rule. A NSW rental has to be structurally sound, adequately ventilated and free of significant dampness.
- The cause decides who pays. A defect or poor ventilation is the landlord's problem. Moisture the tenant let build up can be the tenant's.
- Note it on day one. The NSW condition report has its own mould section. Use it.
- Report it in writing, fast. Tenants must tell the landlord or agent as soon as they notice mould or damp.
- Urgent can mean $1,000. If a fault makes the home unsafe, tenants can be reimbursed up to $1,000 for an urgent repair, paid back within 14 days.
- Evidence wins disputes. Dated photos, moisture readings and a report that names the source carry the most weight at NCAT.
What NSW law says about mould in rentals
Short answer: nothing about mould by name, and a lot about damp.
Section 52 of the Residential Tenancies Act 2010 says a landlord must provide a home that is reasonably clean and fit for habitation. A home isn’t fit unless, among other things, it is structurally sound and has adequate ventilation.
“Structurally sound” is spelled out. Floors, ceilings, walls and supporting structures must not be subject to significant dampness, and the roof, ceilings and windows must not let water in. That’s where most mould claims live.
The landlord also has to keep the home in reasonable repair, unless the tenant’s own breach caused the damage. Having mould noted on the condition report doesn’t cancel that duty, as NSW Fair Trading’s guidance on mould in a rental makes clear.
| Rule | What it means in practice |
|---|---|
| Fit for habitation | The home has to be reasonably clean and fit to live in from day one |
| Structurally sound | Walls, floors and ceilings can't be subject to significant dampness, and the roof and windows can't let water in |
| Adequate ventilation | A wet room with no window and no working fan can fail the standard |
| Reasonable repair | The landlord fixes defects unless the tenant caused them |
| Disputes | A Fair Trading complaint first, then NCAT |
Building fault or how the home is used? How to tell
Short answer: follow the water. Mould that keeps coming back in the same spot, however the room is used, usually points to the building.
| What you see | Likely cause | Usually whose job |
|---|---|---|
| Mould along the base of a wall, with a tide mark | Rising damp or a failed damp course | Landlord |
| A patch on the ceiling under the roof or a box gutter | Roof leak or blocked gutter | Landlord |
| Mould around the shower, spreading behind the tiles | Failed waterproofing membrane | Landlord |
| Windowless bathroom, no working exhaust fan | Inadequate ventilation | Landlord |
| Mould behind furniture on a cold outside wall | Condensation and poor airflow | Often shared: depends on ventilation and use |
| Mould in one room where clothes are dried indoors | Moisture from daily living | Often the tenant |
| Mould back weeks after a surface clean | The source was never fixed | Whoever owns the source |
Rule of thumb: if fixing it takes a tradesperson, it’s probably the landlord’s. If fixing it means opening a window, running the fan and wiping it down, it may be the tenant’s.
Where it’s genuinely unclear, mould inspection and testing settles most arguments. Moisture readings show whether the wall is wet from inside the building or from the air in the room.
Why mould in a NSW rental is so common
Short answer: humidity, older building stock and apartments with internal bathrooms.
Sydney’s coastal humidity, a lot of older brick and fibro stock, and units with windowless bathrooms are a perfect mix. Add blocked box gutters, failed shower membranes in 1970s and 80s units, and long wet stretches through late summer, and you get mould that comes back every year.
Strata buildings add a layer. When water comes from common property, like the roof, the facade or another lot, the fix may sit with the owners corporation rather than your landlord. Your landlord still deals with you, though.
For work anywhere in the state, see how our team handles mould removal in Sydney and across NSW.
What tenants should do
- Check the condition report. At move-in, note any mould or damp in the mould section and attach photos.
- Report it in writing. Email the agent or landlord what you’ve found, where and since when, with photos, and ask for a repair by a clear date.
- Limit the damage. Move belongings off the wall, ventilate and wipe small patches on hard surfaces. Tenants have a duty to reduce their losses too.
- Keep a record. Dated photos, emails, notes of calls and receipts for anything you’ve had to throw out.
- Escalate if nothing happens. Lodge a free complaint with NSW Fair Trading, which can issue a rectification order.
- Apply to NCAT as a last step. It can order repairs, a rent reduction or compensation. Watch the time limits below.
Before you escalate, the Tenants’ Union of NSW mould factsheet explains what evidence helps and where to find free tenancy advice.
What landlords and agents should do
- Act on the first report. A small leak fixed this week costs far less than a ceiling replaced next winter.
- Find the source before anyone cleans. Bleach on the surface while the wall stays wet just restarts the clock.
- Fix ventilation properly. A ducted exhaust fan in a windowless bathroom is cheaper than a dispute.
- Fix the building, then remediate. Leaks, membranes and gutters first, then proper mould remediation.
- Check strata and keep the paperwork. If water comes from common property, tell the owners corporation in writing. Reports and invoices protect you at NCAT.
Urgent repairs and the $1,000 rule
Short answer: a fault that makes the home unsafe can be an urgent repair, and a tenant can be reimbursed up to $1,000 for fixing it.
NSW treats a fault that makes a property unsafe or threatens its structure as an urgent repair. That includes burst water services, serious leaks and serious roof damage. Fair Trading says a fault that makes the home unsafe and creates health risks like mould may count as urgent.
If the landlord or agent can’t be reached or doesn’t act in reasonable time, a tenant can arrange the repair and be reimbursed up to $1,000, paid back within 14 days of written notice. Use a licensed tradesperson, keep the receipts and show you tried to make contact first. The NSW Government’s repairs page sets out the full process.
Fair Trading, NCAT and the time limits
Short answer: complain to Fair Trading first, then apply to NCAT, and don’t sit on it.
A Fair Trading complaint costs nothing. If the landlord refuses the repair, Fair Trading may issue a rectification order with a date for the work. If that doesn’t settle it, NCAT can order:
- Repairs. You show the home isn’t fit or in reasonable repair, you didn’t cause it, and the landlord knew and didn’t act.
- A rent reduction. When mould takes away part of what you pay for, like a room you can’t use. Apply before the tenancy ends.
- Compensation. For example for ruined belongings, if you can show you tried to limit the damage.
Time limits matter. According to the Tenants’ Union of NSW, repair and compensation orders generally have to be sought within 3 months of the missed repair deadline.
Which evidence carries the most weight
| Evidence | Why it matters | Weight |
|---|---|---|
| Condition report with mould noted | Shows whether it was there at the start | High |
| Written repair requests with dates | Proves the landlord knew, and when | High |
| Inspection report with moisture readings | Names the source and separates a building fault from condensation | High |
| Dated photos over time | Shows spread and recurrence | Medium to high |
| Trade quotes or invoices | Shows what the fix involves | Medium |
| Notes on fan and window use | Answers the "it's your lifestyle" argument | Medium |
| Medical certificate | Supports urgency where health is affected | Supporting |
Benefits of dealing with it early
Smaller job, smaller bill
Caught early, mould is often a clean and a fan, not new plasterboard.
Fewer disputes
A cause named early stops the blame game later.
Healthier home
People with asthma, allergies or weak immunity are most affected.
Bond protected
Clear records show the renter reported it and didn't cause it.
Safety while you wait for repairs
Short answer: clean small surface patches carefully, leave anything bigger to a professional, and keep vulnerable people out.
- Small, hard surfaces only. Under about a square metre on tiles or glass, a detergent wash with gloves and a P2 mask is usually fine.
- No bleach on porous surfaces. It fades the stain and leaves the growth.
- Ventilate and heat evenly. Short bursts of fresh air and steady heat cut condensation.
- Protect vulnerable people. NSW Health notes that people with asthma, allergies or weak immunity are most at risk.
For small patches, our step-by-step guide to removing mould yourself covers what works on each surface.
What it costs
Cost depends on the cause, how much material has to come out, and access. Our guide to mould removal costs in Sydney covers prices and who usually pays.
Why tenants, landlords and agents call AllAces
35+ years on the tools
Restoration work across three states, including major flood events in Queensland, NSW and Victoria.
IICRC Certified Firm
Inspections and remediation to AS-IICRC S520:2025.
Reports that name the cause
Moisture readings and photos that hold up with landlords, agents and NCAT.
Sydney and NSW teams
Local crews across Sydney, the Central Coast and Northern NSW.
Fix and verify
Containment, removal, drying and a check that it's back to normal.
Insurance-ready paperwork
Scope, readings and clearance in a format insurers accept.
FAQs
Is mould the landlord's responsibility in NSW?
When the cause is the building, yes: a leak, rising damp, a failed membrane or poor ventilation. A NSW rental must be structurally sound, adequately ventilated and free of significant dampness. If the tenant let moisture build up and didn’t report it, the tenant may be responsible.
Is mould an urgent repair in NSW?
It can be. NSW Fair Trading says a fault that makes the home unsafe and creates health risks like mould may count as urgent. A burst pipe or serious roof leak behind the mould is urgent in its own right.
Can I break my lease because of mould in NSW?
Possibly, if the home isn’t fit to live in, but get advice first. A Tenants’ Advice and Advocacy Service can tell you whether to apply to NCAT, negotiate a rent reduction or end the tenancy, and what to put in writing.
What if the mould is coming from strata common property?
You still deal with your landlord or agent, and the landlord still has to keep the home fit to live in. The owners corporation is generally responsible for repairing common property like the roof, facade and shared pipes, so the landlord or agent takes it up with them. Report it in writing and keep copies.
The bottom line
In a NSW rental, mould follows the moisture. Work out where the water is coming from, put it in writing and keep the evidence, and the “who pays” question usually answers itself.
If you need that cause named, book mould inspection and testing with our Sydney team.
This guide is general information, not legal advice. It’s reviewed every three to six months. Next review due January 2027.
About the author
Nick Roth, Mould Remediation Specialist, AllAces Cleaning & Restoration
Nick has been with AllAces for more than six years and is our most experienced mould remediation specialist. He completed Decon Systems’ Mould Remediation for Technicians course in August 2021. Technicians in every state we work in call on him for the hardest mould testing and remediation jobs, including work with specialised equipment such as Hydroxyl machines.
