Water damage glossary

Category is about health risk and drives the method. Category 1 is water from a sanitary source. Category 3 is grossly contaminated — sewage, floodwater — and porous materials are generally removed rather than dried. Cost tracks it directly: Fixr puts extraction at $3.75–$4.25 per square foot for clean water, $4.10–$6.50 for gray and $7.00–$7.50 for black.

Class is about drying difficulty and drives the duration. Fixr's cost ranges by class run from $150–$400 for Class 1 up to $20,000–$100,000 for Class 4, where water has soaked into low-evaporation materials like hardwood, plaster or concrete.

The other terms you'll meet: mitigation is the emergency work that stops further damage; restoration or reconstruction is rebuilding. An LGR dehumidifier is a low grain refrigerant unit, the professional standard for structural drying. Drying goal is the target moisture level for each material, verified with a meter. Assignment of benefits is a document that lets a contractor bill and negotiate with your insurer directly.

Knowing category and class lets you sanity-check a quote. If someone prices a clean-water kitchen spill like a Category 3 loss, you now have the vocabulary to ask why.

How to choose

Category 1

Water from a sanitary source. Materials can often be dried in place if caught quickly.

Category 2 (gray water)

Contains contaminants that could cause illness. More removal, more sanitizing, higher cost per square foot.

Category 3 (black water)

Grossly contaminated — sewage, floodwater. Porous materials in contact with it are generally removed, not dried. Not a DIY situation.

Class 1 to 4

How much material is wet and how hard it is to dry. Class 4 involves deeply saturated low-evaporation materials and takes the longest.

Drying goal

The documented target moisture content for each material. Equipment should stay until the readings meet it, and come out when they do.