Greencap Flood Response

The recent floods in Victoria, New South Wales and Queensland present multiple challenging situations, and the risks in managing these scenarios are complicated. The information on this page is intended as a first port of call guide for individuals and businesses with flood-impacted properties.

Submitted by Claire.Frost on Fri, 03/04/2022 - 09:44




Greencap is now part of WSP

WSP Occupational Health and Hygiene



⚠️ Update January 2023 - Western Australia Floods ⚠️


Western Australia has bit hit by floods as a result of tropical cyclone Ellie, hitting the town of Fitzroy Crossing, in the Kimberly ranges in the states north west. This is also affecting surrounding areas in Halls Creek, Derby and Broome, and large parts of the Kimberly have now been cut off. 

A full list of affected areas in WA is available here: WA Emergency. Check your risk factor and see if there are any evacuation orders or flood warnings for your area.

Directly after a flood, there arises the risk of mould and hazardous materials that could put you and your family and friends at risk. These could be present in contaminated floodwater, water-damaged homes, and household goods.

Read on for more.

General safety risk considerations following a flood 

  • Only return to your property, and turn on gas, power and water supplies, once authorities have confirmed it is safe to do so. If your property utilises a bore for water supply, it should not be used until it has been tested due to potential for contamination by floodwaters. 
  • Be careful when working in and near flood water. Cloudy water may hide hidden hazards, sharp items or holes, and may be contaminated with chemical contaminants, pathogenic bacteria and/or sewage. 
  • Diesel generators and pressure washes should only be used outside in well ventilated areas, and well away from any doors, windows or vents due to potential for accumulation of hazardous fumes and gases in internal spaces. 
  • Floodwaters may have moved, damaged, buried or exposed asbestos containing materials (ACM), hazardous chemical containers, electrical cabling and wiring, or gas, potable water or wastewater pipework. Further information on asbestos and hazardous substances management is available here
  • Following initial rectification of water-ingress or inundation, mould growth poses a risk to building materials and occupants if drying works are not commenced immediately. Mould testing is recommended. Further information on mould and its management is available here

 Read Greencap's article High demand for community support during Queensland and New South Wales Floods here.

Learn the foundation skills required to understand the health impacts and hazards of mould in Greencap's Online Mould Hazard Awareness Training


Can my property be remediated? 

Appropriately qualified specialist contractors should be appointed to any undertake assessment and remediation works. Best practice dictates that the remediation scope should be developed independently of the remediation contractor, by an experienced and qualified hygienist or Indoor Environmental Professional (IEP). 

  • There are several considerations for properties which have been subject to major flooding damage (inundation or full submersion). Structural damage, and, in the case of timber structures, warping of the superstructure, foundation movement or subsidence, and impacts to roof structures, along with damage to wall linings can make it costly to repair damage. 
  • Swimming pools, septic tanks and leach drains, and Aerobic Treatment Units (ATUs) must be assessed, cleaned and repaired by suitably qualified specialists given the hazardous chemicals, gasses, pathogenic bacteria and/or electrical plant associated with these, in addition to potential movement or subsidence of the items themselves.
  • Soakwells and guttering or drainage pipes are likely to have become blocked with debris and will require flushing and cleaning. Be aware that property drainage which discharges to street drainage/mains sewer may be compromised until street drainage systems are cleared and flowing again.

Listen to Dr Michael Taylor, Greencap Principal Consultant, Mycologist and Mould expert, discuss humidifiers with ABC Radio's Sirine Demachkie 

How to help internal spaces in a property dry out after a flood 

  1. Depending on the residual volume of water in the property, pumping water out using a sump pump, or a wet/dry vacuum is the first step.
  2. Large porous or absorbent items such as couches and rugs will hold large amounts of water, removing them from the property (and disposing of them) will reduce the volume of trapped water and assist in drying.
  3. Large areas of floor coverings (e.g., carpets, laminates, lino) which have been inundated are unlikely to be salvageable. It is important to expose the substructure under these coverings to ensure proper drying and reduce the risk of mould growth. These items should be removed from the property and disposed of.
  4. Porous wall linings such as plasterboard, dry walling, and insulation, will have absorbed large amounts of water and need to be removed to a minimum height of at least 300mm above the upper flood level. This allows greater airflow to, and promotes drying of, the subframe materials of the walls. 
  5. Move large items of furniture away from walls and up off carpets/flooring to increase airflow and reduce trapped moisture and if possible, remove these items to a dry well-ventilated area. Note that it is likely all soft furnishings and contents will require disposal in major flooding situations. 
  6. If it is safe to do so, increasing the air flow through the property will assist in reducing trapped moisture and allow wet items to dry reducing the accumulated high indoor humidity. This could include opening doors and windows, opening cupboards to allow contents to ventilate, and using fans/air movers if power is connected and flood waters have receded.
  7. However, if mould growth has already begun, increasing air movement using mechanical means could potentially spread spores to other non-impacted areas of the building. If mould growth is visible or suspected, ensure that impacted and non-impacted areas are segregated using containment walls combined with HEPA air filtration to produce negative air pressure in the impacted contained area. This should be completed by a suitably qualified contractor.
  8. Dehumidifiers can be used to reduce the humidity of internal spaces once porous items have been removed and disposed of.

 Listen to Dr Michael Taylor talk about How to deal with Mould in your Home with ABC Radio's Indira Naidoo 

What items can be saved from a flood impacted property? 

  • Hard and non-porous items, such as plastic and metals can generally always be saved. Mould growth cannot penetrate the materials these items are made of, and they can often be cleaned by a combination of soap, disinfectant, and gentle scrubbing.
  • Porous items and soft furnishings such as pillows, rugs and couches are very difficult or impossible to completely clean if they have been impacted with flood water and become mouldy, and this process is generally not cost effective. Some items may be professionally laundered, but once mould growth has penetrated pillows and foams, it is unlikely that cleaning or sanitising alone will remove all mould growth.
  • Paper items, books and photographs are also very hard to clean and often are degraded by the growth of mould. If the item is important, it may be possible to damp wipe or vacuum the item, allowing it to be photocopied before requiring disposal in most cases.
  • Clothing may be salvageable if it is professionally laundered, however natural fibres such as cotton may degrade if mould growth is extensive and may be permanently discoloured.
  • Electronic items are almost always unsafe to use or keep once they become wet and should be disposed of appropriately.

 Mould - Frequently Asked Questions

Click each question to view


Mould is the common name given to a broad range of microscopic filamentous fungi, which are related to larger fungi such as mushrooms. Our current understanding of fungi shows that there may be up to 5.1 million fungal species, with currently only 100,000 of them described.


Mould growth occurs on a wide range of organic materials and is often visible as fluffy or downy discolouration. In order to obtain nutrients, fungi excrete digestive enzymes and chemicals to break down their surroundings and absorb the nutrient and mineral compounds that are released. They then grow into new areas once the local environment has been exhausted of food.


Fungi do not require sunlight to grow and can extract nutrients from a wide range of materials including paper, wood, some glues and resins, porous mineral compounds, leather and textiles. Most fungi require high water availability to grow well, and water damage and persistent moisture in building materials or cavities is a high-risk factor for fungal growth.


Fungi reproduce by growing on suitable objects and surfaces in the form of hyphae, which are fine threadlike structures similar to tree roots. Once the fungi has amassed sufficient nutrients and water it will produce a fruiting structure (sporocarp) capable of producing spores – small fungal particles capable of germinating and becoming new fungal colonies.


Spores are microscopic structures, resistant to drying out and in many cases can be easily aerosolised, remain airborne for extended periods of time, and can travel kilometres in distance. In the case of moulds, each colony may produce tens or hundreds of thousands of spores, each capable of colonising a new substrate and beginning the cycle again.



The air we breathe naturally contains fungal spores and fragments, and this changes depending on a wide range of environmental factors including the season, how windy the day is, and the surrounding land use. Inhalation of fungal spores or hyphae rarely causes illness, with normal outdoor air containing anywhere from a few hundred to tens of thousands of spores per cubic metre of air, measured in spore counts per cubic meter (Cts/m3). This means that on a normal day, the average person can inhale somewhere between 10,000 to 1,000,000 or more spores in an outdoor environment.



High levels of growth can cause property damage, allergies and health effects in susceptible individuals, and in rare occasions can cause infections in people who are immunocompromised (have weakened immune systems due to chemotherapy, illness or other conditions).


The primary health risk from mould within buildings is exposure by inhalation of airborne fungal spores, spores containing toxins (mycotoxins), or fragments of fungal hyphae. Exposure to fungal spores and fragments can cause a range of illnesses including allergy-like effects, inflammation of the airways, itchy eyes, and rhinitis.


Ongoing exposure to elevated levels of fungal spores or hyphal fragments can cause sensitisation of the immune system and allergy like effects in susceptible people, resulting in general skin and respiratory discomfort. More serious health effects are generally very rare, and typically do not occur in otherwise healthy individuals.


Exposure to mycotoxins produced by some fungi has been shown to cause a range of health effects and is specific to the mould species present. Mycotoxins are not volatile - they don’t become a gas - and exposure is by inhalation of fungal particles or ingestion of mould contaminated dusts or food.


Not all species or genera of mould produce mycotoxins, with the most common effects of mould growth indoors only causing cosmetic damage to materials (discoloration, bleaching or staining), or unpleasant and musty odours. Some species of mould which have been confirmed to produce mycotoxins do grow in indoor environments, although they do not produce mycotoxins all the time and need specific nutrition, temperate and moisture conditions to produce mycotoxins. The presence of these moulds is often an indicator of risk, but they may not be producing mycotoxins, and exposure to spores and hyphae may be low.


The musty odours caused by microbes growing indoors is due to the production of compounds known as microbial volatile organic compounds (MVOC), a class of over 1000 chemicals which easily become a gas and are often detectable by smell in indoor environments. These compounds may have some health effects at high concentration, primarily as irritants.



Very few people develop mould related illnesses despite daily exposure to fungal spores. Each individual will have a different susceptibility to fungal allergy or infection, based upon their immune system, health status, previous and current exposure. Most people will have a normal, un-heightened immune response when exposed to fungal spores and may show some allergy-type symptoms after elevated exposures with no further effect. After repeated exposures to elevated levels of fungal spores, some individuals may develop sensitivity to fungal sensitivities. This is strongly influenced by your genetic make up, and, exposure to other environmental allergens, with studies showing sensitivity to fungi widely ranging from 0% to 15% of individuals surveyed and more highly related to person specific factors rather than exposure.



Mould growth is always a symptom of a water/moisture problem. As mould requires sufficient moisture to grow, most often the underlying cause is excess moisture in building materials due to leaking pipes, damage to roofing, rising moisture, storm/floodwater inundation, insufficient ventilation or condensation due to areas of large temperature difference. You may find that you have a moisture problem first, and a mould problem second.


Assessing how much mould is a problem can be difficult, as no accepted guidelines exist. Without a complete investigation by a suitably qualified indoor environmental professional (IEP) the true extent of mould growth is very challenging to determine. However, there are guidance documents and general advice which may assist in determining the size of a mould problem and how you should proceed.


Without a complete investigation, the guidance provided by the US-based National Institute for Occupational Safety and Health (NIOSH) Dampness and mold assessment tool1 can be a useful resource to work out if you need assistance in remediating a mould problem.


The NIOSH tool indicates that if mould growth is confined to surfaces (the interior surface of a bathroom ceiling for example) and less than 1m2 it may be possible to clean the surface or to remove and replace the affected material yourself. The NIOSH tool goes on to indicate that if the mould growth extends beyond an area of 1m2, or is occurring within a wall cavity or ceiling space, it may be unsafe or impractical to attempt to repair the damage and remediate the area yourself.


Mould growth of this extent is often indicative of an underlying problem and may require the engagement of a qualified tradesperson to fix the source of the moisture ingress, and qualified restorer to remove the affected materials, clean the area and reconstruct the removed building materials.


1 NIOSH. Dampness and Mold Assessment Tool for General Buildings. In: Cox-Ganser J, Martin M, Park JH, Game S, Morgantown WV, eds: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH); 2018.



The source of the moisture which has caused the mould to grow would have to be investigated prior to any mould remediation works. For building materials that are semi-porous or porous (have small holes or spaces that can hold liquid or air) with water damage caused by failure of plumbing or water ingress from a storm event, it is often best to engage appropriately qualified contractors to undertake assessment and remediation works.


However, if mould growth is visibly less than 1m2, is present on non-porous materials, and the source of the moisture is not due to damage to pipes or structural materials, then the home occupier may wish to undertake mould cleaning works themselves (e.g., mould growth to bathroom tiles as result of poor ventilation). This can be undertaken using a variety of different methods, including steam cleaning, and the use of mould cleaning solutions using microfibre cloths. Ensure that personal protective equipment is used, including (but not limited to) appropriate gloves and a well fitted half face respirator with organic vapour filters. It is important to note that susceptible people should not carry out any form of mould remediation (i.e., people who have respiratory issues, are immunocompromised, or have identified health risk factors).



If the issue has been caused by damage to your property by failure of plumbing, water ingress from a storm event or flood etc., the damage may be covered by your insurance. In this instance, you should begin the claims process with your insurance company who should engage suitably qualified contractors. For mould remediation, contractor must have industry recognised training i.e. is certified by the IICRC2 or RIA3 for water damage and microbial remediation.


It is extremely important that any mould and moisture investigation, as well as sampling, is carried out by a suitably qualified hygienist, indoor environmental professional (IEP) or expert.


2. Institute of Inspection Cleaning and Restoration Certification
3. Restoration Industry Association



If you are a residential tenant, you may be able to use an estimate of the size and extent of mould growth with supporting mould sample results which indicate active mould growth to request your landlord remediate/repair your home. Residential tenancy laws will differ by state but all place a legal obligation upon the landlord to provide premises which are fit for habitation.


Examples of this legislation exists across all states in Australia and you should familiarise yourself with any sections which apply to your circumstance.


State/Territory Requirement
NSW The landlord must ensure that the residential premises in a reasonable state of cleanliness and fit for habitation by the tenant. (s 52(1) Residential Tenancies Act 2010 (NSW)), and provide and maintain the residential premises in a reasonable state of repair (s 63(1) RTA)
ACT The landlord must ensure that the residential premises in a reasonable state of cleanliness and fit for habitation by the tenant on commencement of a lease. The lessor must maintain the premises in a reasonable state of repair having regard to their condition at the commencement of the tenancy agreement (Residential tenancies Act 1997)
VIC The residential rent provider must ensure that the rented premises are provided and maintained … in a reasonably fit and suitable condition for occupation (s 68(1)(b) Residential Tenancies Act 2007 (Vic)).
SA The landlord must ensure that the premises, and ancillary property, are in a reasonable state of repair at the beginning of the tenancy and will keep them in a reasonable state of repair having regard to their age, character and prospective life (s68(a) Residential Tenancies Act 1995). And it is the landlord’s obligation to repair: If – the state of disrepair is, unless remedied, likely to result in personal injury or damage to property or undue inconvenience (s68(3)(b) Residential Tenancies Act 1995).
QLD The premises are fit for the tenant to live in (s 185(2)(b) Residential Tenancies and Rooming Accommodation Act 2008 (Qld)).
NT The landlord: (a) must ensure that the premises and ancillary property are in a reasonable state of repair when a tenant enters into occupation of the premises; and (b) must maintain the premises and ancillary property in a reasonable state of repair, having regard to their age, character and prospective life. (s57(1) Residential Tenancies Act of Northern Territory 1999).
WA The lessor: must maintain the premises in a reasonable state of repair having regard to its age and character and must conduct any repairs within a reasonable period after the need for the repair arises; and must comply with all requirements in respect of buildings, health and safety under any other written law insofar as they apply to the premises. Residential Tenancies Act 1987.



A mould and moisture investigation is typically carried out as part of an insurance claim and the building owner is not directly responsible for the costs. These investigations usually require several attendances to evaluate the size of the water damage or mould problem, develop a scope of remedial works and to check to ensure all the mould has been removed.


For a routine investigation of a typical home the cost would be in excess of $1500, for a single site visit within a capital city metropolitan area, with more complicated investigations of larger homes, buildings or commercial premises requiring access to roof spaces and subfloors being more expensive. It is important to check your insurance policy to determine if the cost may be covered by your insurer, however providing Greencap with a detailed outline of the problem greatly assists us in providing an appropriately scoped and costed job. This can be done through our online enquiry form or in consultation with one of our experts.



Greencap does not carry out mould remediation work, as we are independent advisors within the remediation project. Mould remediation costs are very variable due to the different types of building damage that can cause mould growth. A small leak detected quickly may only require targeted drying works to be carried out and may not require any removal or cleaning works to be completed, whilst an ongoing leak within wall, floor or ceiling voids will likely require extensive mould remediation and structural works to be carried out.



Spores collected from the air and from surfaces do not need to be grown in order to be analysed. This type of sampling is called ‘total’ sampling or sometimes referred to as ‘non-viable’ sampling however this is not strictly true as this type of analysis will pick up both live and dead spores but won’t be able tell the difference between them. ‘Total’ sampling allows mycologists at Greencap to count and identify all the spores present in a sample using a microscope.


Using this method Greencap’s mycologists identify fungi to genera level. However, if the species of mould is required to be identified, like for instance in a health risk assessment, further targeted ‘viable’ sampling, where spores are collected and grown under controlled conditions on a nutrient agar plate, will be required to be performed. Greencap can also undertake this sampling however the analysis is currently performed at an external third-party laboratory.



News - Mould


Monitoring & management of water in buildings




Mould's Damaging Impact on Building Health & Structure




Managing Mould & Water Ingress Risks in Flood-Impacted Properties




Understanding & Assessing Mould Risks




The A-Z of Mould - INCLEAN Magazine




Mould Outbreak Affecting Properties Across New South Wales




The A-Z of Mould - INCLEAN Magazine



Contact Greencap

[email protected]


Michael Taylor

Principal Consultant/Mycologist - Health & Safety


Cedric Cheong

Team Manager OCHYG & IEQ


Ian Crew

Principal Consultant


Greencap acknowledges the Traditional Owners of Country throughout Australia and recognises their continuing connection to land, waters and culture.  We pay our respects to their Elders past, present and emerging.