19/08/2025
When we respond to Water damages, you may over hear us saying things like “this is a CAT 1, 2 or 3 water damage. You may wonder what we mean by CAT 1 or CAT 2 or even CAT 3 water loss.
Here is what the ANSI/IICRC S500 Standard for Professional Water Damage Restoration defines as CATEGORIES of water.
“Category of Water: the categories of water, as defined by this document, refer to the range of contamination in water, considering both its originating source and quality after it contacts materials present on the job site. Time and temperature can affect or re**rd the amplification of contaminants, thereby affecting its category. Restorers should consider potential contamination, defined as the presence of undesired substances; the identity, location, and quantity of which are not reflective of a normal indoor environment; and can produce adverse health effects, cause damage to structure, systems, or contents, or adversely affect the operation or function of building systems.
Category 1: Category 1 water originates from a sanitary water source and does not pose substantial risk from dermal, ingestion, or inhalation exposure. Examples of Category 1 water sources can include, but are not limited to: broken water supply lines; tub or sink overflows with no contaminants; appliance malfunctions involving water-supply lines; melting ice or snow; falling rainwater; broken toilet tanks, and toilet bowls that do not contain contaminants or additives.Category 1 water can deteriorate to Category 2 or 3. Category 1 water that flows into an uncontaminated building does not constitute an immediate change in the category. However, Category 1 water that flows into a contaminated building can constitute an immediate change in the category. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water. Odors can indicate that Category 1 water has deteriorated.
Category 2: Category 2 water contains significant contamination and has the potential to cause discomfort or sickness if contacted or consumed by humans. Category 2 water can contain potentially unsafe levels of microorganisms or nutrients for microorganisms, as well as other organic or inorganic matter (chemical or biological). Examples of Category 2 water can include, but are not limited to: discharge from dishwashers or washing machines; overflows from washing machines; overflows from toilet bowls on the room side of the trap with some urine but no f***s; seepage due to hydrostatic pressure; broken aquariums, and punctured water beds.Category 2 water can deteriorate to Category 3. Once microorganisms become wet from the water intrusion, depending upon the length of time that they remain wet and the temperature, they can begin to grow in numbers and can change the category of the water.
Category 3: Category 3 water is grossly contaminated and can contain pathogenic, toxigenic, or other harmful agents and can cause significant adverse reactions to humans if contacted or consumed. Examples of Category 3 water can include, but are not limited to: sewage; wasteline backflows that originate from beyond any trap regardless of visible content or color; all forms of flooding from seawater; rising water from rivers or streams; and other contaminated water entering or affecting the indoor environment, such as wind-driven rain from hurricanes, tropical storms, or other weather-related events. Category 3 water can carry trace levels of regulated or hazardous materials (e.g., pesticides or toxic organic substances).”
