Drying & repair

Category 1, 2 and 3 water: why the source matters

Updated September 29, 2026

Short answer

Restoration professionals classify water by contamination. Category 1 is clean (a supply line), Category 2 is gray (a washer or dishwasher discharge), and Category 3 is contaminated (sewage, outside floodwater). The higher the category, the more material must be removed instead of dried.

Containment and protective equipment set up for sewage cleanup

Category 1 — clean water

From a sanitary source: a broken supply line, a faucet, a water heater or melting ice. Most materials can be dried if work starts quickly.

Category 2 — gray water

Contains some contamination: washing machine or dishwasher discharge, toilet overflow with urine but no feces, aquarium water. Carpet pad is usually removed; surfaces are cleaned.

Category 3 — black water

Grossly contaminated: sewage, toilet backflow with feces, and floodwater from outside, including monsoon runoff. Porous materials it touched are removed and the area is disinfected.

Water gets worse over time

Clean water that sits for a few days, especially in warm conditions, can become Category 2 or 3 as bacteria grow. That's another reason to start drying fast.

Questions

Is monsoon floodwater really Category 3?

Water that flowed across the ground from outside picks up soil, animal waste and chemicals, so it's treated as contaminated.

Can carpet soaked with gray water be saved?

Sometimes the carpet can be cleaned; the pad is usually replaced.

Who decides the category?

The technician, based on the source and how long the water sat, often following the IICRC S500 standard.

Editorial note: this guide is general information for Arizona homeowners, not professional, legal or insurance advice. For your situation, talk to a licensed contractor and your insurer.