Classes of Water Damage

How Classes are Defined

The classes of water intrusion are defined by the IICRC, the governing body that creates the standards for professional water damage restoration. The four classes are a classification of the estimated evaporation load, and are based on the approximate amount of wet surface area (mainly as a percentage of the overall area), and the permeance and porosity of affected materials remaining within the drying environment at the time drying is initiated.

In addition to classes of loss, we also determine the category of water damage based on the source and potential contaminants.

Four Classes of Water Damage

Class 1: This has least amount of water absorption and evaporation load.

A small amount of the room is wet, representing ~5% of the combined floor, wall and ceiling surface area in the space. Affected materials described as low evaporation materials such as plaster, wood, concrete, masonry, or low evaporation assemblies such as multilayer wallboard, multilayer subfloors, gym floors, etc. have absorbed minimal moisture.

Class 2: Represents a significant amount of water absorption and evaporation load.

A larger portion of the room has been affected - from 5-40% of the combined floor, wall and ceiling surface area with wet, porous materials such as carpet, gypsum board, fiber-fill insulation, concrete masonry unit, and textiles. Low evaporation materials have absorbed minimal moisture.

Class 3: This applies to greatest amount of water absorption and evaporation load.

In a Class 3 situation, wet, porous materials (carpet, gypsum board, fiber-fill insulation, textiles) represent more than ~40% of the combined floor, wall and ceiling surface area in the space. Low evaporation materials have absorbed minimal moisture.

Class 4: Represents specialty drying situations for deeply held or bound water.

Water intrusion that involves a significant amount of water absorption into low evaporation materials or low evaporation assemblies. Hardwoods, plaster, brick, stone, and concrete have absorbed greater amounts of mf moisture and may require special methods, longer drying times, or substantial water vapor pressure differentials.

Three Categories of Water Damage

Category 1: Clean Water

Sources might be a bathtub overflow or refrigerator line leak. Category 1 can degrade to Category 2.

Category 2: Grey Water

Examples include 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 feces; seepage due to hydrostatic pressure; broken aquariums and punctured water beds. 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 deteriorate to Category 3.

Category 3: Black Water

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 sewage; waste line 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.