These categories designate the TYPE of water that is involved in the water damage!!!
Category 1: Clean Water.
A clean water source is one that does not pose substantial harm to humans. Examples of clean water sources may 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 falling rainwater – not that which flows over the soil or through multiple structural components- broken toilet tanks, and even toilet bowls that do not contain contaminants or additives. Once a clean water source contacts other surfaces and materials, its condition may change to grey water or black water as it dissolves or mixes with soils and other contaminants over time.
Category 2: Grey Water.
Unsanitary or grey water contains some degree of contamination. Potentially, it could cause substantial discomfort or sickness if consumed by humans, and it carries microorganisms or nutrients for microorganisms. Category 2 grey water examples may include, but are not limited to: discharge from dishwashers or washing machines, overflows from washing machines, overflows of toilet bowls with some urine (no feces), broken aquariums, and punctured water beds. All of these may contain chemicals or biocontaminants (fungal, bacterial, viral, algae), or other forms of contamination. Time and temperature aggravate Category 2 grey water contamination significantly. The Indoor Air Quality (IAQ) may be compromised. Grey Water in flooded structures that remains untreated longer than 48 hours can change from Category 2 grey water to Category 3 black water.
Category 3: Black Water.
Category 3 black water always contains pathogenic agents. Grossly unsanitary, black water sources are those that arise from sewage or other contaminated water entering a structure. Sewage contains the expected urine and feces; but it could also contain dangerous chemicals or medical wastes. Toilet backflows that originate from beyond the toilet trap are considered to be Category 3 black water situations, regardless of visible content or color. This category includes all forms of sea water, ground surface water, and rising water from, rivers or streams. They carry silt and organic matter into structures and create Category 3 black water situations. In situations where structural materials and/or contents have been heavily contaminated with such materials as pesticides, heavy metals, or toxic organic substances; the water damage is considered to be Category 3 black water. There are serious Indoor Air Quality (IAQ) issues with this type of water damage.
These Categories Of Water Damage inform you of the precautions that MUST be taken BEFORE you place airflow on the drying job to reduce health hazards for occupants and technicians.
* IICRC Standard S500: Standard and Reference Guide for Professional Water Damage Restoration.