Common sources and the category they usually start in
| Source | Typical starting category | What usually happens to porous materials |
|---|---|---|
| Broken supply line or faucet | Category 1, clean | Often extracted and dried |
| Water heater tank failure | Category 1, usually | Often extracted and dried if handled quickly |
| Dishwasher or washing machine overflow | Category 2, gray | Carpet pad usually replaced; other materials evaluated |
| Toilet overflow without waste | Category 2, gray | Pad replaced; carpet cleaned and evaluated |
| Toilet overflow with waste or sewer backup | Category 3, black | Porous materials it contacted are removed |
| Groundwater or surface flooding from outdoors | Category 3, black | Porous materials it contacted are removed |
| Fire sprinkler discharge | Often treated as Category 2 | Evaluated case by case; ceiling tile usually replaced |
| Rooftop or HVAC condensate | Varies | Depends on what the water ran through on the way down |
Where the categories come from
The three-category system appears in the IICRC S500 standard for water damage restoration, which most insurers and contractors use as the common reference. Category 1 is water from a sanitary source that does not pose substantial risk if touched or swallowed. Category 2 carries significant contamination and could cause illness. Category 3 is grossly contaminated and can carry pathogens, including sewage and floodwater that has crossed the ground.
The category is separate from the class of water damage, which describes how much water there is and how hard it will be to dry. A small sewage backup is Category 3 even if it only covers a closet floor; a large clean-water leak across an entire office floor is Category 1 but a high class of drying difficulty.
Time and travel can raise the category. Clean water that sits on a basement floor for several days in summer warmth, or that runs through a dirty crawlspace and back into the house, is no longer clean. That is one reason fast extraction matters even for supply-line leaks.
What the category changes on the job
- IfCategory 1 and found quicklyExtraction and drying in place is usually the plan for carpet, walls and many contents.
- IfCategory 2Expect more removal of pad and some porous items, plus cleaning of surfaces before drying.
- IfCategory 3Expect porous materials it touched to be removed, workers in protective gear, containment where needed and cleaning before drying.
- IfCategory is unclear, such as a slow leak of unknown originAsk how the contractor decided and have the reasoning written in the job notes.
Common questions
Who decides the category?
The restoration contractor usually assesses it and records the reasoning. Your insurer's adjuster may review that decision, so it helps if the source and timing are documented with photos.
General information for Aurora, not a quote or professional advice. In an emergency, call 911.