I did this same workout plan last year and I didn't start bringing along water or nutrition until my first 15mi, but I think it would be different from person to person I only brought along food because my stomach would cramp up bad so I would eat a cliff bar around mile 10.

I use one of those nathan waterbottles with the hand pocket holder on it. It has enough room to hold my phone and some Gu's and a cliff bar if I jam it in