Mould inspection: what it finds, what it costs, who pays

People book a mould inspection to find out what the mould is. What they need to find out is where the water is coming from. Mould only grows where something keeps a surface damp, and until that source is found, cleaning is temporary. A good inspection is therefore closer to leak detection than to a laboratory test, and the questions to ask before paying for one follow from that.

What an inspection is actually looking for

HealthyWA lists the common sources of indoor moisture: surface water leaking into the building, wet foundations such as rising damp, rain leaking in through the roof or walls, poor ventilation, showering and cooking without exhaust fans, clothes dryers and unflued gas heaters, and indoor plumbing leaks (HealthyWA, Mould and dampness). An inspection is a process of ruling those in or out, room by room. The tools are ordinary: a moisture meter on walls and skirting, a thermal camera to show cold or wet patches behind plaster, a torch in the roof space and the subfloor, and sometimes a small hole in the plasterboard to look inside a cavity.

What comes back should answer four questions:

1. Source. Leak, rising damp, rain getting in, or condensation from how the home is lived in. These have different fixes and, in a rental or a strata building, different people responsible.
2. Extent. How much material is affected, including what is hidden. WA Health guidelines treat contamination no greater than 1 m² as a simple job and larger areas as complex (WA Department of Health, Guidelines for Managing Mould and Dampness Related Public Health Risks in Buildings), so extent decides the scale of the remediation.
3. Whether it is still wet. Active moisture means the source is still running; dry readings around old staining may mean it was fixed.
4. Who fixes what. HealthyWA’s point is that different professionals may be needed to identify and clean the mould and to fix the underlying problem — a plumber, a roofer, a builder.

Spore counts do not answer any of those. That is why mould testing has its own page: the health departments’ position is that sampling is generally unnecessary where mould is visible, and there is no Australian guideline value to compare a result with.

Three different things called an inspection

Before you buy. The NSW Government says a pre-purchase report will include significant defects such as rising damp, but a building inspector would not normally check concealed damp-proofing, plumbing or drainage, and in a strata unit normally assesses only the interior and immediate exterior of the unit (NSW Government, Pre-purchase inspection reports when buying a home). Consumer Affairs Victoria’s checklist for buyers says mouldy walls, lifting tiles, peeling paint or pools of water in wet areas can indicate excessive moisture (Consumer Affairs Victoria, Inspect properties before you buy). In Queensland, only a licensed residential building inspector can complete pre-purchase building inspections, and the QBCC says the report is not a warranty against future defects; for a particular worry it suggests a more detailed report from the right expert (Queensland Building and Construction Commission, Before you buy and sell). If the pre-purchase report flags damp or mould, that is the moment to book a moisture inspection or a plumber before exchange, not after.

After a leak. Where the mould followed a burst pipe, a leaking shower or a roof leak, a plumber’s leak detection may find the source faster and more cheaply, and the mould extent can be scoped with the drying. The leak detection guide covers that route and the water utility allowances.

What a mould inspection costs

No government or regulator publishes a price for a mould inspection, and the hipages figures are national. The comparison worth making is between the inspection and what it is meant to save: if it finds a leaking pipe or a failed membrane, the remediation quote that follows can be scoped to the actual area instead of priced for the worst case. Ask for the inspection and any removal to be quoted separately, so the inspection is not a sales visit for the removal. The mould removal guide sets out removal prices.

Rentals: who arranges it and who pays

No state law read for this site puts the cost of an inspection on one side directly. What the rules do is decide who is responsible for the mould, and the inspection is the evidence of that.

Victoria. Consumer Affairs Victoria says renters may need to give the rental provider proof that mould is dangerous and needs urgent repair, for example an assessment report by an occupational hygienist, environmental health professional or expert from the local council (Consumer Affairs Victoria, Pests, infestations and mould), and that renters may be able to get the rental provider to pay them back for a health assessment by applying to VCAT.

New South Wales. NSW Fair Trading says who is responsible depends on how the mould developed: the landlord where it came from a repair not made in reasonable time or inadequate ventilation, possibly the tenant where moisture built up because the home was never ventilated (NSW Fair Trading, Mould in a rental property). An inspection that names the source settles which side of that line a case falls on.

When the landlord or agent wants to send someone to look, the notice periods depend on the reason for entry:

A tenant who arranges their own inspection keeps control of the report; one arranged by the landlord is the landlord’s document. Either way, ask for the moisture readings and photographs, not just the conclusion.

Who does it, and what to ask

No state source read for this site licenses “mould inspector” as a title. The health departments point to occupational hygienists where the source cannot be found; for a suspected leak, a licensed plumber; for a roof, a roofer. Before booking, ask:

• Will you find the moisture source, or only report the mould?
• What instruments will you use, and will the readings and photos be in the report?
• Will you look in the roof space and subfloor, and will you open a cavity if needed?
• Do you also sell removal? If so, quote the two separately.

For an insurance claim, the inspection’s value is the same: the insurer will want to know what made the building wet. Mould cover and limits covers how that plays out.

Common questions