Type 3 water damage, also called Category 3 or black water, is damage from grossly contaminated water such as sewage, toilet backflow with waste or outside floodwater. It can carry bacteria, viruses and chemicals. Under the IICRC S500 standard it is the most serious category, and it always needs professional cleanup.
Where Type 3 water comes from
- Sewer line backups into tubs, showers and floor drains
- Toilet overflows that contain waste
- Septic system backups on rural properties
- Monsoon floodwater and runoff entering the home
- Clean or gray water that sat long enough for bacteria to grow
In Arizona, two sources come up most: sewer backups during heavy monsoon rain, when lines are overloaded, and floodwater running in through garages and patio doors. Floodwater can look clear and still carry soil, animal waste and chemicals.
Why it is dangerous
Black water can carry germs that cause stomach and skin illness. Wet materials can also grow mold, and the CDC says mold exposure can cause coughing, wheezing, a stuffy nose and burning eyes in some people. Children, older adults and anyone with a weakened immune system should stay away from the affected area.
What can be saved
| Material | Usual outcome after Category 3 water |
|---|---|
| Tile, sealed concrete, metal, glass | Cleaned and disinfected |
| Solid wood furniture | Sometimes cleaned, depending on exposure |
| Carpet and pad | Removed and discarded |
| Drywall and insulation that got wet | Cut out and replaced |
| Upholstered furniture and mattresses | Usually discarded |
| Food, cosmetics and medicine that got wet | Discarded |
How professionals clean it up
- Contain the area so contaminants don't spread to clean rooms.
- Remove the water with emergency water extraction.
- Remove porous materials that touched the water.
- Clean and disinfect every affected surface.
- Dry the structure with structural drying and confirm with moisture readings.
Crews wear protective gear for this work. Don't try to clean black water yourself. For backups, see our sewage cleanup service, and for the full repair, water damage restoration.