If you have a flood from an overflowing sink or broken pipe that would be
Depending on the source of the water, the cleanliness of the surface the water goes through and the time the water sits before being dried out, water can quickly degrade from Cat 1 to Category 3. This is when you start to have those bacteria and mold odors. This is why whenever there is a Cat 3 water damage it is our strong recommendation to remove all wet materials and not dry in place. This is also why when you have a freshwater loss it is important to start the drying process right away!