Maximum of filtered water (60-70%) is reabsorbed in the proximal tubule, with or without Vasopressin. This is independent of the fluid and electrolyte status of the body and is caused by the osmotic gradient created by Na+ reabsorption. Obligatory water reabsorption- (Independent of ADH)- 85% -        Proximal tubule- 60-70% -        Descending limb of loop of Henle- 15% Facultative water reabsorption- (ADH dependent)- 15% This depends on fluid and electrolyte status of the body -        Late distal tubule -        Cortical collecting duct Medullary collecting duct