Categories of Water Damage

Category 1 - Clean Water

Clean water originates from a source that does not pose substantial harm to humans. Examples of clean water sources may include, but are not necessarily 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.

Clean water that has contact with structural surfaces and content materials may deteriorate in cleanliness as it dissolves or mixes with soils and other contaminates, and as time elapses.

IICRC S500 (p. 3)

Category 2 – Gray Water

Gray water contains a significant level of contamination and has the potential to cause discomfort or sickness if consumed by or exposed to humans. Gray water carries microorganisms and nutrients for microorganisms. Examples of gray water sources may include, but are not necessarily limited to, discharge from dishwashers or washing machines, overflows from washing machines, overflows from toilet bowls with some urine (no feces, sump pump failures, seepage due to hydrostatic pressure, broken aquariums and punctured water beds. Gray water may contain chemicals, biocontaminants (fungal, bacterial, viral, algae) and other forms of contamination including physical hazards.

Time and temperature aggravate category 2 water contamination levels significantly. Gray water in flooded structures that remains untreated for longer than 48 hours may change to category 3 - black water.

IICRC S500 (p. 3)

Category 3 – Black Water

Black water contains pathogenic agents and is grossly unsanitary. Black water includes sewage and other contaminated water sources entering or affecting the indoor environment. Category 2 water that is not removed promptly from the structure may be reclassified as category 3 water. Toilet backflows that originate from beyond the toilet trap is considered black water contamination, regardless of visible content or color.

Category 3 water includes all forms of flooding from seawater, ground surface water and rising water from rivers or streams. Such water sources carry silt and organic matter into structures and create black water conditions.

The water is considered to be category 3 water in situations where structural materials and/or contents have been contaminated with such contaminants as pesticides, heavy metals, or toxic organic substances.

IICRC S500 (p. 3)