I think water is best for most of us, if we aren’t sweating profusely for extended periods.

If you have an ileostomy, then you need sports' drinks. If you have a j pouch, water should be fine.

I drink water and incorporate a 12oz glass of pedialyte daily. Sports drinks have way too much sugar which can cause increased bathroom trips 

Sports drinks tend to have a high sugar concentration which can pull more fluid into the small bowel and actually contribute to dehydration.  Water is great.  If you are losing lots of fluids through sweat, or output try a sugar free sports drink or make your own.  There are lots of on line recipes.

Thank you for all your replies. I will stick to water.

What about sugar free sports drinks for ileostomy?

Personally, I do really well with daily electrolytes. I use the Ultima brand, and drink 80 ounces of water daily with about three scoops of the electrolytes in total between my two bottles. I've gone on vacation before and forgotten my electrolytes. After about two days I feel super lethargic and almost like I have the flu. The Ultima is sugar free, but sweetened with stevia.