Water reabsorption in renal tubules varies at different levels. The maximum reabsorption is at:
Sites of water reabsorption in the kidney: Proximal tubule (65% of the filtered water) Descending thin limb of Henle's loop (10%) Collecting-duct system (where the fractional reabsorption is the most variable) Ref: Eaton D.C., Pooler J.P. (2009). Chapter 6. Basic Renal Processes for Sodium, Chloride, and Water. In D.C. Eaton, J.P. Pooler (Eds), Vander's Renal Physiology, 7e.
PCT
Collecting duct
Descending Loop of Henle
Ascending limb of Henle