Let’s Talk About Water Damage: Classes and Categories

Sep 23, 2021

There are three different categories of water damage, as well as four different classes of water damage. This can get a little bit confusing, so it helps to take a closer look at how water damage is professionally defined.

What does “Category” mean?

This is the kind of water that has invaded. 

Category 1

Refers to a source of water that does not pose substantial threat to humans and classified as “clean water”. Examples are broken water supply lines, tub or sink overflows or appliance malfunctions that involves water supply lines.

Category 2

Water that “contains significant contamination and has the potential to cause discomfort or sickness if contacted or consumed by humans.” Examples can include Punctured water beds.

Category 3

Known as black water. This is considered grossly contaminated with pollutants including fungi and bacteria.  Examples can include but are not limited to sewage, toilet backflows that originate from beyond the toilet trap, all forms of flooding from seawater, ground surface water and rising water from rivers or streams.

What does “Class” mean?

This is the amount of water and the likely or anticipated rate of evaporation based upon the number and type of wet materials in the affected space. There are four classes of water.

Class 1

This most likely will only affect part of a room or area or may include larger areas with materials that have absorbed minimal moisture. (Least amount of water, absorption, and evaporation).

Class 2

This affects at least an entire room of carpet and cushion. Water has gone up the walls less than 24 inches. There is moisture remaining in structural materials like plywood, particle board, structural wood, VCT, and concrete. (Large amount of water).

Class 3

This may have come from overhead. In a class 3 the ceilings, walls, carpet, insulation, and sub floor are saturated in the entire area. (Greatest amount of water).

Class 4

This includes wet materials with very low permeance porosity such as hardwood, plaster, brick, concrete, lightweight concrete, and stone. In these cases, there are deep pockets of saturation, which require very low specific humidity. Class 4 losses typically require longer drying times and special methods.

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