Categories of Water

There are three categories of water, as defined by the IICRC. These categories of water refer to the range of contamination in water, considering both its originating source and its quality after it contacts materials present on the job site. Time and temperature can also affect the quality of water, thereby changing its category. In general, any materials saturated with category 3 water should be removed.

Category 1 Water (Clean Water)
Water that 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; and falling rainwater. However, once clean water leaves the exit point, it may not remain clean once it contacts other surfaces or materials.

Category 2 Water (Grey Water)
Water that 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 include, but are not limited to: discharge from dishwashers or washing machines; overflows form washing machines; overflows from toilet bowls on the room side of the trap with some urine but no feces; broken aquariums; and punctured water beds.

Category 3 Water (Black Water)
Water that is grossly contaminated and can contain pathogenic, toxigenic, or other harmful agents. Examples of category 3 water include, but not limited to: sewage, toilet backflows that originated beyond the toilet trap regardless of visible content or color; all forms of flooding from seawater, ground surface water, and 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. Such water sources may carry silt, organic matter, pesticides, heavy metals, regulated materials, or toxic organic substances.