I have used Garden Grocer multiple times and been pleased with the service.
If the only thing you need is bottled water and you are willing to spend a some of time:
multi-packs (I think they are 24's, but might be 12's) of Nestle purelife bottled water are at available at SOME resorts, usually in the fridge area of the gift shop. I have seen them at Art of Animation, Fort Wilderness and a few others. Some places, like Wilderness Lodge's Merchantile don't have them that I have ever seen.
Of course, you would have to get there and then haul it back to your resort. doable, but requires strategy.
SW