The minerals in the water also help the yeast.Here is your friendly salmon, swimming upstream, but I use distilled water. :< I know this is not the popular choice and the thought is that some of the "minerals" found in bottled water would be missing from the wine. My thinking on this is (and we are talking about kits because that is normally the only time water is added) the producers of the kits remove just water from the grape in order to produce the concentrated product we buy. In removing water (H2O), they do not remove minerals or anything else. All I am doing with distilled water is adding back H2O and nothing else. I would add further that in doing so I have never had a problem.
I'm lucky enough to have really nice well water. No chlorine worries and the slight minerality comes through in the Rieslings and Gewurztraminers. If you have a friend who has quality well water you might try filling a few jugs at their house.
That's the scarier thing about spring water... It isn't required to meet the same testing level as our city water.Tap water is fine as long as you know whats in it. I really doesn't matter if it is from a municipal well or a private well. City water will have chlorine it which will evaporate if left on the counter overnight. There are over 600 potential contaminates that can be in water. Our city tests the water you say?