Water is very important not only for the diet but for your long term health in general. If you want the best tasting water, I would get bottled water that is in a glass container. The plastics leech from the plastic containers and thus you are drinking plastic. Plastics can mess up the body and should be avoided at all costs. The chemical industry has never done testing on the effects of plastics on humans.
I would not sweeten the water but drink it straight up. If you get the cleanest, most pure water there is, you will like the taste.
You could chug it if you wanted to like beer or coffee in comparison, then you won’t taste it much.
I love water and I find it difficult to stay hydrated on this diet.