Mould Inspection in Perth

Perth's wet season and when mould appears

The Bureau of Meteorology describes Perth's climate as hot-summer Mediterranean. About 80% of the region's yearly rain falls between May and October (BOM, Perth climate and water). A house can look dry through a long summer and then show stains, damp patches and a musty smell once the winter fronts arrive.

Dry years do not rule mould out. BOM recorded 622 mm in the Perth region in the year to June 2025, about 20% under the long-term average of 791 mm and the seventh below-average year in a row. Leaking showers, blocked gutters and rooms closed up against the cold still put water where it does not belong. A buyer inspecting in February may see none of it, which is why the report records the season of the visit.

Landlord and tenant duties for mould in WA

WA splits responsibility by cause. Consumer Protection's rental maintenance guidance says mould from faults in gutters or other fixtures should be fixed by the landlord. It also lists mould linked to the age of the home, or to having no ventilation fan or window, as a landlord matter. The tenant may be responsible where mould comes from not using the bathroom fan or opening windows.

The same page sets minimum standards for rentals, including weatherproofing and freedom from hazards such as leaking roofs. Mould is not listed as a separate standard. A report that separates a building fault from day-to-day condensation gives both parties something firmer than opinion. Our landlord and tenant guide covers the national picture. This is general information, not legal advice.

WA Health's 2024 report and the role of sampling

In February 2024 WA Health published Indoor Mould: Health Risk Assessment and Management, prompted by mould in homes after the 2022-23 Kimberley floods. The WA Health report cites Australian studies suggesting that between a third and half of all homes in Australia have indoor mould growth. Our guide to mould after flooding covers that situation.

The report notes that WA guidance does not recommend surface or air sampling of mould spores to set the level of health risk. It does say sampling may help show how far mould has spread, especially where hidden mould is suspected. That matches how a Perth inspection is run. The moisture source and visible growth come first, and samples are added where they answer a question an inspection cannot, such as growth behind a wardrobe or under flooring. See hidden mould behind walls and floors and why identification matters.

Who books mould inspections across Perth

Consumer Protection has named mould among the complaints it receives about newly let rentals, alongside plumbing, leaking roofs and pests (Consumer Protection announcement). Common requests include:

• tenants who want the growth and moisture documented before asking for repairs
• property managers who need to know whether a fault or household habits sit behind a complaint
• buyers looking at a house in the dry months who want to know how it behaves in winter
• households who return after weeks away on a FIFO roster to find growth in closed rooms
• insurers and owners after a burst pipe or storm leak (see the mould insurance guide)

What happens during a Perth mould inspection

Test Australia's suitably qualified occupational hygienists take moisture readings in walls, floors and ceilings and look at the building inside and out, including gutters, downpipes and garden levels against brick walls. Thermal imaging is used where it helps, and it shows temperature, not mould. Where samples are taken, the report names the laboratory and states any accreditation that applies. Test Australia itself is not NATA-accredited.

Reports are available within 5 business days of the laboratory results being received. The national mould inspection page sets out the general method, and moisture control explains why the water source matters more than the growth itself.

Checking a Perth home after repairs by others

Test Australia does not remediate, repair or recommend firms that do. That leaves it free to return once someone else has fixed the leak and dealt with the growth, and to record whether the walls have dried and whether growth remains. Brick can take a while to dry, so say when the work finished. You can read more about the types of assessment work Test Australia does and how fees are built in what affects mould testing fees.

Steps in a Perth mould inspection

1. Describe the problem. Send photos, the rooms affected, whether it worsens between May and October, and any repairs already done. Say whether the home is rented, being bought or under a claim.
2. Agree the scope in writing. A written fee proposal states which rooms and buildings are covered and whether sampling is likely to add anything. You approve it before a date is set.
3. Trace the moisture. On the day, readings at several heights and outside checks separate rising damp, leaks and condensation.
4. Sample where it locates hidden growth. Air or surface samples are taken only where they help show the extent of growth, and they travel under chain of custody.
5. Receive the signed findings. The report links the likely cause, the extent and any results, notes the season of the visit and states what was not accessible.

Mould inspection questions from Perth