fanny packs work well. they have pockets for water bottles and extra room so your pockets aren't bulging.
in reply to the post above mine, i have a silly fast metabolism. (Have done since i was young) But also push myself pretty hard so end up walking at a pretty fast speed so will end up sweating alot, im guessing thats the reason for drinking alot? (generally if my legs aint hurting - im not walking fast enough!!)
It's the same with me Ian H, sweat like nuts and despite drinking myself bloated before hand and during i still get cramp sometimes and don't pee for days afterwards (sorry chaps)...definately out of shape.
(any VitC in the powder will neutralise the sterilising effect of the iodine/chlorine)