Category 1
Clean water, at the moment it arrives
A supply line, a tub overflow, a water heater, melting ice. It came from somewhere sanitary and it does not pose a health risk on contact.
This does not stay Category 1. Left undried, bacterial growth moves it toward Category 2 — commonly within 48 to 72 hours, though it depends on temperature and on what it is sitting in rather than on a clock.





