Boil 6 cups of water. Pour it into a juice container.
Drop 3 teabags into the hot water, as follows (some variation permitted. This is what I used):
1 Dry Desert Lime (Numi brand)
1 Green Tea
1 Wildberry Delight (Tetley)
Leave it for an hour. Then put it in the fridge (with the teabags still in it). Wait for a few hours, or overnight or whatever.
Pour yourself a glass when you're thirsty. You won't believe how good it tastes.