1. Storing water for later use. Humans build dams and reservoirs to store water for use during dry periods or for use in areas where water is scarce. Other organisms may store water, but not typically on the same scale as humans.

2. Purifying water. Humans use a variety of methods to purify water, including boiling, filtering and treatment with chemicals. Other organisms can purify water through natural processes, such as filtering, but cannot use chemicals to do so effectively as humans.