Water categories describe contamination, not simply the amount of water in a room. The distinction helps explain why two apparently similar leaks can need different restoration work.
Guidance reviewed 28 September 2026.
AS-IICRC S500:2025 is Australia’s adopted professional water-damage restoration standard. See the IICRC publication announcement. The outline below is for property owners and managers; a site assessment and the applicable standard are needed to determine the work.
Category 1: water from a clean source
This describes water originating from a sanitary source without substantial contamination risk. A clean source is a starting point, not a permanent label: what the water contacts and conditions at the property also matter.
Category 2: contaminated water
This category involves significant contamination that can cause discomfort or sickness through exposure. It needs a different approach from a small clean-water spill. Do not decide the category from the apparent colour of the water.
Category 3: grossly contaminated water
Sewage and contaminated rising floodwater are examples that call for particular caution. Keep people away from affected areas and seek an assessment; do not start ordinary carpet drying or move contaminated items through clean rooms.
Rainwater and elapsed time do not decide the category by themselves
The IICRC’s 2026 position statement on weather-related water explains that wind-driven rain and top-down water ingress are not automatically Category 3. Inspection and evidence of contamination are needed.
The statement also explains that the source, contact with materials, time and temperature affect the assessment. There is no single 24-hour or 48-hour category-switch rule to apply to every incident. This is not a reason to delay: tell the restorer when the water was first noticed and whether wetting is continuing.
This position statement addresses ANSI/IICRC S500:2021. It should be read in that context alongside the Australian standard, rather than treated as a new Australian edition.
What to ask about the proposed restoration work
- What supports the category? Ask what was found about the source, water spread and affected materials, and what remains uncertain.
- What happens before drying? Ask whether contamination controls, cleaning or removal are needed before restorative drying begins.
- Which materials can be retained? Ask for the reasons behind proposed removal and the limits of any drying attempt. A category label alone is not a complete item-by-item scope.
- What will be documented? Discuss photographs, moisture findings, the agreed work, later changes and the checks used to assess progress.
- Is another specialist needed? Clarify any need for an independent assessment or separately arranged building, plumbing or electrical work.
Do not assume that a chemical spray makes affected materials suitable to keep, or that a surface feeling dry proves the assembly beneath it is dry. Decisions should be explained in relation to the actual damage and agreed scope.
Tell us what happened
When contacting Reztor, give the property suburb, the suspected source, when you noticed it, the rooms affected and any access limitations. Photographs can help explain the situation when they can be taken safely; they do not replace an inspection.
Reztor’s own team carries out its restoration work. We do not subcontract that restoration work. Repairs to the source and building reinstatement are separately arranged, and the proposed scope should make those responsibilities clear.
Call 1800 739 867 or send enquiry details and photographs. Learn more about our water-damage restoration services and how structural drying works.
Further reading: the IICRC S500 overview and EPA guidance distinguishing clean-water drying from contaminated-water work.