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The Categories and Classes of Water Damage

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The Categories and Classes of Water Damage

Did you know there are three categories and four classes of water during a water loss?   Understanding each type, it’s sources and the risks for each during your restoration process is important.  When dealing with water inside your home or property, time is always of the essence.


Category 1: This category is made of liquid from a clean and sanitary source.  While this water may start as clean water it can turn into category 2 rather quickly if not dealt with immediately.

Cat 1 Sources Include:

  • Faucets
  • Water fountains
  • Toilet Tanks



Category 2: Known as “Grey Water”, this water may have levels of contaminants that can cause illness when ingested.

Cat 2 Sources Include: 

  • Washing Machine Overflows
  • Leaking Dishwashers
  • Flush from Sink Drains


Category 3: This is the worst category of water and could cause illness or even death if not dealt with properly.

Cat 3 Sources Include:

  • Sewer Backup
  • Standing Liquid that contains Bacterial Growth
  • Flooding from Rivers or Streams
  • Toilet Overflows that Contain Feces.


  • Class 1: Only part of a room is affected in a class 1 water loss. This class is the easiest to deal with and has a slow evaporation rate. Affected materials will contain little to no carpet and only consist of low permeance materials like concrete or plywood.
  • Class 2: With a fast evaporation rate, class 2 will affect an entire room that contains carpeting where moisture has traveled up the walls at least a foot. Moisture remains in structural materials.
  • Class 3: The fastest evaporation rate of the four classes, class 3 usually has a source that has started from above. The entire room will be saturated including ceilings, walls, insulation, sub-floors and carpet.
  • Class 4: Specialty drying situations when there has been enough time and water to saturate materials like brick, stone, or hardwood make up class 4.

In all cases, water in your home or property needs to be dealt with quickly but also professionally before your small issue turns into a large problem. Even clean water source losses can create thousands of dollars in costly repairs if not dried out properly the first time. Mold can grow quickly behind walls, in ductwork and throughout your flooring. Trust the professionals at Mammoth Restoration to ensure your property is dried effectively the first time.

24 hours a day, 365 days a year, We will be there within 2 hours! (888)-495-5211