The human body is a quite remarkable machine of flesh and bone however it still has limitations.
Human Body can go 32 days without sleep (Everson et al. 1989), but how long without water. Please read the statement from Randall K. Packer, a professor of biology at George Washington University regard this question:
It is impossible to give an answer to this seemingly simple question because many variable factors determine a person’s survival time. Under the most extreme conditions, death can come rather quickly. For example, a child left in a hot car or an athlete exercising hard in hot weather can dehydrate, overheat and die in a period of a few hours. An adult in comfortable surroundings, in contrast, can survive for a week or more with no, or very limited, water intake.

References:
Everson, C.A., Bergmann, B.M., Rechtschaffen, A. (1989). Sleep deprivation in the rat: III. total sleep deprivation. Sleep, 12(1), 13-21.
https://www.scientificamerican.com/article/how-long-can-the-average/