travel and rhum

Hiking south rim loop at big bend and Emory peak in a day. AllTrails says it is 17 miles and I wanted to see how much water I should take? 6 foot, 170lbs male. I plan on taking 2 Cliff bars, banana, and pb&honey as well. My osprey holds 3L and I was planning on taking an extra liter with nalgene. Is 4L enough?

On a recent 5.5 hour hike I drank over 3 L of water and not once did I feel like I needed to pee on the hike..I only went after the hike. Has anyone else experienced this? I just don't know how I can be drinking so much water and not need to pee. The only thing I can think of is that when I'm in such an active, high alert state my body doesn't feel like it can pee until I'm more relaxed.