Water can enter a building in many ways. Local flooding, leaking roofs and broken plumbing are all potential water sources that can cause damage to belongings and possible structural damage as well as create potential indoor environmental and indoor air quality concerns.
It's important for people to understand what type of water has entered a structure so that it can be properly remediated and appropriate measures can be taken to protect workers and building occupants from any potential hazards.
Depending on the water source and possibly the length of time it remains in a building, it may contain bacteria, viruses, mold, chemicals, protozoa and even parasites. There are three categories of water that are typically used when classifying a water damage or flooding event.
Category 1 Water, also known as Clean Water, does not typically result in an immediate health threat to building occupants. This type of water is considered clean at its point of release. Examples include broken water supply lines and the overflow of a sink or tub. Even in properties with this type of initial water damage, mold can begin to grow in as short as 24 hours. It may also become increasingly contaminated over time and as it interacts with materials in the property.
Category 2 Water, also known as Grey Water, typically contains a significant amount of biological or physical contaminants that can cause sickness when humans are exposed or if it is accidently consumed. Examples include water discharged from a dishwasher or washing machine. Category 2 Water, that is not promptly removed or has remained stagnant for some time, may at times be reclassified as Category 3 Water.
Category 3 Water, also known as Black Water, is grossly contaminated. It may contain harmful pathogens, microbes and chemicals that could cause illness. Sources include sewage, seawater, rising water from rivers or streams, ground surface water or standing water.