I'm not sure which OR water pouch you are using, but I've used this http://www.rei.com/product/402189 simple one for years. I have it attached to the right side of the hipbelt on my Granite Gear Ozone. Weighs about an ounce. Costs about $5. Holds an Aqua Fina bottle perfectly.

It makes the water very accessable. I reach for the bottle, take a drink, and replace it when I'm on the go and without even setting down my trekking poles.