Black water is water that is contaminated and unsanitary. It may not always appear “dirty,” so it is important to know the source of the water. Flooding from sea, river, and lake water is classified as black water because of the presence of microorganisms and unknown chemical pollutants. Sewage water is also black water. Items that have been heavily damaged by black water should probably be discarded, but always check with a dry cleaner to see if they can be restored.