Mould is a serious concern in Australian homes, posing risks to both property and health.

Estimates suggest that up to half of all Australian homes may be affected by mould, with renters particularly vulnerable[i]. Poor housing conditions—especially in the rental sector—combined with recent wet weather patterns such as La Niña have created ideal conditions for mould to thrive.

According to Asthma Australia, any level of mould is considered unsafe for health, regardless of whether a person has asthma. Exposure can worsen existing respiratory conditions and even increase the risk of developing asthma.

While it’s commonly believed that mould only grows in warm, humid environments, winter can be just as problematic. Cold temperatures may slow down the growth of mould spores, but poor ventilation and condensation from indoor heating create the damp conditions that mould needs to flourish.

Mould is a type of fungi—part of the same group as yeast and mushrooms—and is found both indoors and outdoors. When airborne mould spores settle on damp surfaces inside the home, they can begin to grow and spread rapidly.

It thrives in moist, poorly ventilated areas such as walls, ceilings, insulation, mattresses, carpets, tiles, and wood.

Ultimately, it is the landlord’s responsibility to provide a mould-free rental. In most states and territories, landlords are legally required to ensure a property meets minimum standards—this includes providing new tenants with a clean, safe, and mould-free environment. These obligations may vary depending on local state or territory legislation.

Even in vacant properties, mould isn’t always visible—so early detection is key. Tenants should promptly report any signs of mould or mildew to their Raine & Horne Property Manager, along with any issues that could lead to mould growth, such as roof leaks, plumbing problems, or water leaks through walls or windows. Poorly sealed windows and inadequate ventilation in bathrooms and kitchens can also contribute to mould formation.

Once notified, your Raine & Horne Property Manager will arrange for qualified tradespeople to assess and address the issue.

Some properties—due to age, structural design, location, or ventilation—may be more susceptible to mould. In these cases, landlords are generally responsible for organising and covering the cost of remediation.

Blocked roof gutters are another common cause of mould, particularly after storms or heavy rainfall. Tenants should report blocked gutters, as landlords are responsible for ensuring they are cleared. Left unchecked, overflowing gutters can cause water damage and promote mould growth, potentially leading to costly structural repairs.

While landlords are responsible for maintaining the property to prevent mould, tenants are responsible for cleaning visible surface mould, as outlined in their tenancy agreement. Fortunately, there are practical and eco-friendly cleaning products available that make this task safer and easier than ever.

To find out more about your obligations as a tenant, reach out to your local Raine & Horne office without delay.

[i] https://asthma.org.au/about-us/media/new-report-goes-inside-australian-homes/#:~:text=50%25%20of%20Australians%20have%20had,people%20with%20and%20without%20asthma.