I would not worry about water on the main whitney trail as there are quite a few places to fill up. From Trail Camp to the summit and back will be your longest stretch without water (although I've heard there is water on one of the switchbacks going up to Trail Crest).

Tom Harrison maps are very good maps.

Here is a link to (one of?) the Alltrails maps. I don't know if you can see the full map with elevation profile without a subscription. https://www.alltrails.com/trail/us/california/mount-whitney-via-mount-whitney-trail

If not, let me know and I can screenshot it for you.