Category 1 water
Category 1 typically starts as a relatively clean source such as a fresh supply-line break. Even then, timing matters. Clean water can degrade if it sits too long or moves through dirty materials.
Category 2 water
Category 2 usually contains more contamination and requires greater caution. This may include certain overflows or discharge that is not raw sewage but is no longer considered clean.
Category 3 water
Category 3 involves grossly unsanitary water, including sewage-related sources. Safety, containment, sanitation, and material removal decisions are much more serious here.
Why the category matters
- It changes what protective steps should be taken
- It affects what porous materials may need removal
- It changes how cleaning and sanitation are approached
- It influences what occupants should avoid before the area is stabilized
One more complication
The category can change over time. Water that started cleaner may become more contaminated if it stays in place, travels through dirty building assemblies, or mixes with other sources.