Kangaroo rats are common to the deserts in Mexico and the Southwestern United States. They can survive up to 5 years without drinking water and have learned some interesting adaptations that allow them to live in one of the driest environments on the planet.
I can tell you with confidence that rats without water can live longer than humans. Once, rats appeared in the garage, although there was no access to water, and no food either. Until I set up rat traps, they did not disappear. What did they eat and what they drank is unknown.