With a bit of lemon juice and salt. Good for kidneys (and all kinds of things) but I also think I tend to commit to this because it’s not just plain water.
I keep falling out of the habit and getting back into it, but I put a pinch of salt, a pinch of potassium (in the form of cream of tartar) and a pinch of coconut sugar in a glass with a good squeeze of lemon and my filtered structured water and guzzle it first thing on an empty stomach. Also sometimes I fill a carafe with water, lemon juice and bits, sliced cucumber and mint leaves with a pinch of salt to drink through the day, great in summer