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 fast |
| Dishwasher or washing machine overflow | Category 2, gray | Pad usually replaced, other materials evaluated |
| Toilet overflow without waste | Category 2, gray | Pad replaced, carpet cleaned and evaluated |
| Toilet overflow with waste, or a sewer backup | Category 3, black | Porous materials it touched come out |
| Groundwater or surface flooding from outdoors | Category 3, black | Porous materials it touched come out |
| 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 comes from the IICRC S500 standard for water damage restoration, which most insurers and contractors treat as the shared reference. Category 1 comes from a sanitary source and poses no substantial risk if touched or swallowed. Category 2 carries significant contamination and could make people sick. Category 3 is grossly contaminated and can carry pathogens, including sewage and floodwater that has crossed the ground.
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 that only covers a closet floor is still Category 3. A large clean-water leak across a whole office floor is Category 1, with a high class of drying difficulty.
Time and travel can raise the category. Clean water that sits on a basement floor for several warm summer days, or runs through a dirty crawlspace and back into the house, isn't clean anymore. That's one more reason fast extraction matters, even for a supply-line leak.
What the category changes on the job
- IfCategory 1, found fastThenThe usual plan is to extract and dry carpet, walls and many contents in place.
- IfCategory 2ThenExpect more pad and porous items to come out, and surfaces to get cleaned before drying.
- IfCategory 3ThenExpect the porous materials it touched to come out, workers in protective gear, containment where needed and cleaning before drying.
- IfThe category is unclear, as with a slow leak of unknown originThenAsk how the contractor decided, and get the reasoning written into 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 call, so photos of the source and the timing help.
General information for Aurora, not a quote or professional advice. In an emergency, call 911.