What to do after water damage: Construction procedure for a property owner Owner’s Procedure
Water damage rarely announces itself politely. A dishwasher hose lets go overnight, a storm drives rain under flashing that has done its job for fifteen years, a hot water system fails while everyone is at work. By the time it is noticed, the clock has already started on decisions that determine whether this costs a few hundred dollars in fans and dehumidifier hire, or tens of thousands in structural rectification and mould remediation.
Australia has only just gained its first dedicated national reference standard for this exact scenario. In 2025, Standards Australia adopted AS-IICRC S500, the local adaptation of the internationally recognised ANSI/IICRC S500:2021 framework for professional water damage restoration. Before that, restoration practice varied enormously between operators, insurers and regions, with no single agreed benchmark. This guide sets out the procedure a property owner should follow from the moment water is discovered, the standard now guiding restoration professionals, and where the line sits between a job you can safely handle yourself and one that needs a licensed contractor.
What Counts as Water Damage
Water damage is any unwanted water intrusion affecting a building’s structure, fittings or contents, from a burst pipe or overflowing appliance to storm ingress, roof leaks, or rising groundwater. It is not limited to the visible pool on the floor. Timber framing, insulation and the cavity behind plasterboard absorb moisture long before it becomes visible, which is exactly why the procedure below starts before any drying equipment is switched on.
Why the First Hour Matters
Two clocks start the moment water enters a property, and they run at very different speeds.
The safety clock is immediate. Standing water near power points, switchboards or appliances is a genuine electrocution risk, and it is the most common reason people are injured during what should be a straightforward cleanup.
The mould clock is slower but less forgiving. NSW Health and the enHealth guidance published through the Australian Centre for Disease Control both point to the same window: surfaces need to be dry and clean within 48 hours to prevent mould colonisation. Left beyond that window, mould stops being a cleaning problem and becomes a health one, it can trigger asthma, aggravate allergic conditions, and irritate eyes, skin and airways, with people who are immunocompromised or already have respiratory conditions at greatest risk.
The Standard Now Governing This Work: AS-IICRC S500:2025
AS-IICRC S500:2025 is Standards Australia’s adopted version of the ANSI/IICRC S500:2021 Standard for Professional Water Damage Restoration. It describes the procedures and precautions restoration professionals should follow when working on residential, commercial and institutional buildings and the contents inside them. It is not a regulatory requirement, a restorer does not break the law by ignoring it, but it is now the industry reference point insurers, regulators and property owners can hold a contractor’s work against.
Two things follow for a property owner. First, when you are assessing quotes from restoration contractors, it is reasonable to ask whether their process follows AS-IICRC S500. Second, once any reinstatement building work is required, for example replacing a section of wet area lining or flooring, that work needs to meet NCC 2022 Volume Two Part H2, Damp and Weatherproofing, which sets the performance requirement that a building must protect against damage or health risk caused by moisture and redirected surface water. AS3740 is the accepted construction solution most commonly used to demonstrate compliance for wet area waterproofing on reinstatement.
The Three Water Categories
Not all water damage carries the same risk, and the category of water involved changes almost every decision that follows, including whether materials can be dried and kept or need to be removed and replaced.
Category | Typical source | Risk level | What it means for you |
Category 1, clean water | Supply line failure, tap, rainwater before contact with the ground | Low, if addressed within 24 to 48 hours | Most porous materials can usually be dried and retained |
Category 2, grey water | Washing machine or dishwasher discharge, shower or bath overflow, aquarium failure | Moderate, contains some contaminants | Requires more caution, some materials may still need replacement |
Category 3, black water | Sewage backup, floodwater that has touched the ground, toilet overflow with waste | Severe, health hazard | Professional remediation required, affected porous materials generally cannot be saved |
Category can also escalate with time. Clean water left untreated for more than 48 hours starts interacting with building materials and can degrade toward Category 2 conditions, which is another reason the first response window matters more than the size of the spill.
The Step by Step Procedure
1. Make the area safe before anything else
If water has reached power points, switchboards or appliances, do not enter the area. Turn off electricity at the main switch only if it can be reached without walking through standing water. If reaching the switchboard means walking through water, call an electrician instead of taking the risk yourself. Power should not be restored until an electrician has confirmed it is safe.
2. Stop the source if it is safe to do so
If the water is coming from an internal plumbing failure, shutting off the main water supply is usually the fastest way to stop further damage. If the source is a roof leak during a storm, this step may need to wait until conditions are safe.
3. Document everything before you touch anything
Photograph and video the damage from multiple angles before any cleanup begins, floors, walls, ceilings, furniture, electronics, and especially structural materials like timber framing and plasterboard. The Insurance Council of Australia is specific on this point, insurers expect this evidence, and it is far harder to establish after items have already been moved or disposed of.
4. Remove standing water
Use a wet and dry vacuum or pump for anything beyond a minor spill. The longer water sits on flooring, the further it migrates into subfloor and skirting, and the more materials end up needing replacement rather than drying.
5. Identify the water category
Match the source against the three categories above. This determines what protective equipment is needed and whether affected porous materials, carpet, underlay, some plasterboard, can realistically be saved or should be assumed a loss.
6. Remove and protect belongings
Lift furniture onto blocks or foil, remove rugs and soft furnishings that have absorbed water, and separate anything that can be dried from anything that is likely a write off. Don’t discard repairable items before they’ve been photographed for the claim.
7. Ventilate and begin drying
Open windows where weather allows, run fans and a dehumidifier, and start drying within the first 24 hours. This is the single biggest lever against the 48 hour mould window.
8. Contact your insurer early
Lodge a claim as soon as it’s safe to do so, before extensive cleanup, and ask directly what your policy covers. Burst pipes are typically covered as sudden, accidental damage, provided there is no evidence of long term neglect. Storm and flood cover is frequently a separate arrangement, do not assume it is automatically included.
9. Decide whether this is a DIY job or a professional one
Covered in detail in the next section, but as a rule, anything beyond a small, clean water spill addressed within hours is worth at least a professional assessment, even if you end up doing some of the work yourself.
10. Monitor for the following five to seven days
Even after visible drying, check daily for musty odours, discolouration, or softening in walls and skirting. Mould can establish in wall cavities before it is visible on the surface.
The First Week, Hour by Hour
Timeframe | What to do | What happens if ignored |
Hour 0 to 1 | Make safe, stop the source, begin documentation | Electrical injury risk, water spreads further into subfloor and framing |
Hours 1 to 24 | Remove standing water, remove and protect belongings, begin ventilation and drying, contact insurer | Category 1 water can begin degrading toward Category 2 conditions |
Hours 24 to 48 | Continue active drying, get a professional moisture assessment if the area is significant | This is the mould establishment window per NSW Health and enHealth guidance, once passed the risk changes materially |
Days 2 to 7 | Monitor drying progress, arrange any structural assessment, finalise insurance documentation | Hidden moisture in wall cavities can establish mould that isn’t visible until it’s extensive |
Week 2 onward | Confirm moisture readings are back to normal before reinstatement work begins | Closing up walls or flooring over residual moisture traps the problem and often causes it to resurface |
Common Mistakes
- Restoring power before an electrician has confirmed it is safe.
- Cleaning up and disposing of damaged items before photographing them for the insurance claim.
- Assuming a small visible spill means the damage is only small, without checking subfloor and wall cavities.
- Closing up walls or replacing flooring before moisture readings confirm the area is genuinely dry.
- Treating storm or flood water the same as a clean supply line leak, when the contamination risk and required response are very different.
- Waiting more than 48 hours to begin serious drying, and losing the narrow window before mould has a chance to establish.
- Assuming home insurance automatically covers flood damage, when many policies treat it as a separate, opt in cover.
- Engaging a contractor without asking whether their process follows the AS-IICRC S500:2025 standard.
DIY or Call a Professional
Situation | Reasonable to DIY | Call a professional |
Small clean water spill, addressed within hours | Yes, mop, fan, dehumidifier | Not usually required |
Category 1 water affecting more than a few square metres of flooring | Sometimes, with hire equipment and close monitoring | Recommended, moisture can be trapped in subfloor without professional readings |
Any Category 2 or 3 water | No | Always, contamination and health risk require professional remediation |
Water has reached a wall cavity, ceiling, or insulation | No | Always, hidden moisture and mould risk are very hard to assess without equipment |
Structural timber, flooring, or wet area waterproofing needs replacing | No | Always, this is licensed building work subject to NCC compliance |
Insurance Claims: What Insurers Actually Expect
The Insurance Council of Australia’s guidance is consistent on a few points that make claims go more smoothly. Safety comes first, don’t re-enter a property until it has been cleared as safe, and don’t restore electricity until an electrician has inspected it. Contact the insurer promptly to lodge the claim and get guidance on the process specific to the policy. Photograph and video damage thoroughly before cleanup starts. Items that pose a health risk can be removed and disposed of, but only after they have been documented, repairable items should not be discarded unless they genuinely need to be.
On coverage, burst pipes and similar sudden, accidental failures are typically covered under standard home insurance, provided there’s no evidence the damage resulted from a long standing, unaddressed problem. Flood damage is treated differently by many insurers and is not always included automatically, it is worth checking this specifically rather than assuming.
Indicative Cost Guide
These are broad Australian ranges for context only, actual cost depends heavily on the extent of the damage, the category of water involved, and whether structural or wet area reinstatement work is required. Always get a written quote before committing to work.
Scope | Indicative range (AUD) |
Minor clean water response, drying equipment hire, small area | $300 to $1,200 |
Moderate restoration, professional extraction and structural drying, one or two rooms | $2,000 to $8,000 |
Major restoration with Category 2 or 3 contamination and materials replacement | $8,000 to $25,000+ |
Structural rectification, framing, flooring, or wet area waterproofing reinstatement | Highly variable, quote required, often $10,000+ |
Tools and Equipment for the First Response
- Wet and dry vacuum or submersible pump
- Fans and a dehumidifier
- Moisture meter, for checking whether materials are actually dry before closing up any work
- Protective gloves and, for Category 2 or 3 water, a properly rated mask
- Furniture blocks or foil to lift belongings off wet flooring
- Camera or phone for documentation
Compliance and Quality Checklist for Reinstatement Work
- Moisture readings confirmed back to normal range before any lining, flooring, or insulation is replaced
- Restoration process followed AS-IICRC S500:2025 principles for the water category involved
- Any wet area waterproofing reinstatement meets NCC 2022 Volume Two Part H2, using AS3740 as the construction solution where applicable
- Drying logs and moisture readings kept as records, useful for both quality assurance and any insurance follow up
- Visible inspection for mould or odour at 7, 14 and 30 days after the incident
- Any electrical work signed off by a licensed electrician before power is restored
Long Term Prevention, Gold Coast and Brisbane Properties
Storm season and high humidity make South East Queensland properties more exposed than most, and most water damage Buildamax sees on site traces back to a small number of preventable causes.
- Clear gutters and downpipes before storm season, blocked gutters are one of the most common causes of water finding its way behind cladding and fascia
- Check wet area waterproofing in bathrooms and laundries periodically, membrane failure behind tiles is a slow, often invisible cause of internal water damage
- Service hot water systems and washing machine hoses on a schedule rather than waiting for failure
- Check roof flashing and sealant annually, particularly after a severe storm season
- Ensure site drainage directs water away from the building, not toward it, this is a common issue on renovated or extended properties where original grading has changed
A Typical Gold Coast Scenario
A common pattern on renovation and extension projects: a washing machine hose fails overnight in a laundry adjoining a timber framed hallway. By morning, the hallway carpet is visibly wet, but the water has already tracked under the skirting and into the subfloor space. The homeowner mops the visible area and runs a fan, assuming the job is done. Ten days later, a musty smell develops along the hallway wall, moisture had been trapped in the wall cavity the whole time. What would have been a same day extraction and drying job becomes a wall lining replacement and a week of remediation. The difference was a moisture reading behind the skirting on day one, not on day ten.
Expert Tips
- If in doubt about whether power is safe, always wait for an electrician, the cost of a call out is negligible next to the risk
- A moisture meter costs less than a single day of hire equipment and tells you things a visual inspection cannot
- Photograph before you clean, not after, this single habit prevents more insurance disputes than anything else
- Treat any water that has touched the ground outside, or come from a toilet or sewage line, as Category 3 until proven otherwise
- Ask any restoration contractor directly whether their process follows AS-IICRC S500:2025, it is a fair question and a genuine differentiator between operators
Frequently Asked Questions
How long does it take for mould to grow after water damage?
Mould can begin establishing within 24 to 48 hours of water exposure, which is why NSW Health and enHealth guidance both point to that window as the priority for drying and cleaning affected surfaces.
Is it safe to stay in a house with water damage?
It depends on the extent and category of the water. Category 1 water affecting a small area is generally low risk once power safety is confirmed. Category 2 or 3 water, or any damage affecting electrical systems, warrants professional assessment before deciding whether the area is safe to occupy.
Does home insurance cover water damage in Australia?
Sudden, accidental damage such as a burst pipe is typically covered under standard home insurance, provided there’s no evidence of long term neglect. Flood damage is often treated as separate cover and is not automatically included in every policy, check your specific policy wording.
What is the difference between Category 1, 2 and 3 water?
Category 1 is clean water from a source like a supply line. Category 2, grey water, carries some contamination, typically from appliance discharge. Category 3, black water, is grossly contaminated, from sources like sewage or floodwater that has touched the ground, and requires professional remediation.
Can I dry out water damage myself?
For a small, clean water spill addressed within a few hours, yes, with fans, a dehumidifier and a moisture meter to confirm the result. Anything larger, any Category 2 or 3 water, or any water that has reached wall cavities or ceilings, is a job for a professional.
What is AS-IICRC S500:2025?
It is Standards Australia’s newly adopted national standard for professional water damage restoration, based on the international ANSI/IICRC S500:2021 framework. It is not a legal requirement but is now the industry benchmark for how restoration work should be carried out.
How do I know if my walls are still wet after water damage?
Visual dryness on the surface does not confirm the wall cavity or subfloor is dry. A moisture meter reading, ideally from a professional, is the only reliable way to confirm before any lining or flooring is reinstated.
What should I photograph before cleaning up water damage?
Every affected area from multiple angles, floors, walls, ceilings, furniture, electronics, and any structural material, before you move or dispose of anything. This documentation is what your insurer will expect to support the claim.
Should I turn off the power after water damage?
Only if the switchboard can be reached safely without walking through standing water. If reaching it means walking through water, do not attempt it, call an electrician instead.
How much does water damage restoration cost in Australia?
It varies widely by scope. A small clean water response might run a few hundred dollars in equipment hire, while major restoration involving contamination and material replacement can run into tens of thousands. Always get a written quote.
What is NCC Part H2 and why does it matter for water damage repairs?
NCC 2022 Volume Two Part H2 sets the performance requirement that a building must be protected from damage or health risk caused by moisture and redirected surface water. It applies once reinstatement building work, particularly wet area waterproofing, is needed after water damage.
Can water damage cause structural problems?
Yes. Sustained moisture in timber framing can lead to rot and loss of structural capacity over time, and untreated moisture in wall cavities is a common cause of mould that isn’t visible until it has spread significantly.
Is storm damage covered by home insurance in Australia?
Often yes for wind and rain damage through a failure like a roof leak, but flood specifically, water rising from rivers, storm surge or overland flow, is frequently a separate, sometimes optional, cover. Check the specific definitions in your policy.
What is the first thing I should do when I discover water damage?
Confirm the area is safe, particularly around electricity, before doing anything else. Only once safety is confirmed should you move to stopping the source and documenting the damage.
Do I need a professional even for a small water leak?
Not always. A small, clean water spill caught and dried within hours is often manageable without a professional. The judgement call is about category, extent, and how quickly it was caught, not just the size of the visible puddle.
How long should drying equipment run after water damage?
Until moisture readings confirm the affected materials are back to a normal range, not a fixed number of days. Removing equipment based on how things look rather than what they measure is a common mistake.
What is black water and why is it dangerous?
Black water, Category 3, is grossly contaminated water from sources like sewage backup or floodwater that has touched the ground. It carries a genuine health risk, and affected porous materials generally cannot be cleaned and saved, they need to be removed.
Who do I call first after water damage, my insurer or a restoration company?
Both, early. Safety comes first, then contact your insurer to understand the claims process, and get a professional assessment if the damage is beyond a small, clean water spill. Insurers generally expect prompt notification either way.
Summary
Water damage is won or lost in the first 48 hours. Make the area electrically safe, stop the source, document everything before cleanup, identify whether the water is clean, grey or black, and start active drying immediately rather than waiting to see how it looks. Australia’s newly adopted AS-IICRC S500:2025 standard now gives property owners a genuine benchmark to hold restoration contractors to, and any reinstatement building work needs to meet NCC 2022 Part H2 for damp and weatherproofing. When in doubt about category, extent, or electrical safety, the cost of a professional assessment is small next to the cost of getting it wrong.
Need a Professional Assessment on the Gold Coast or Brisbane?
Buildamax provides building consultancy and construction management across the Gold Coast, Brisbane and Byron Bay, including assessment and reinstatement work following water damage. If you’re dealing with water damage right now and are unsure whether it needs professional attention, request a consultation and we’ll help you work out the right next step, no pressure, no obligation.