The IICRC S500 Standard of Water Classification
The Institute of Inspection, Cleaning and Restoration Certification (IICRC) classifies water damage into three progressive categories based on the level of biological contamination:
- Category 1 (Clean Water): Originates from sanitary sources such as clean supply lines or fresh water heater leaks. Safe for human contact initially.
- Category 2 (Grey Water): Contains chemical or microbial contamination, such as water heater sediment overflow, dishwasher discharge, or clean water left stagnant for over 24 hours.
- Category 3 (Black Water): Highly contaminated water containing sewage, pathogens, or outdoor storm surge floodwaters. Requires full biohazard containment.
Learn more about our biohazard-grade cleanup protocols on our flood water removal services page.