Tap water doesn't necessarily have any more or less mineral content than bottled mineral water. The variation between mineral water brands and the variation between tap water sources (mostly: well water vs surface) is much larger than any difference between bottled and tap.

If you live in an area with hard tap water you're essentially drinking "mineral water" out of the tap.

Here's some data for ya:

Mineral Content of Tap Water in Major North American Cities: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1495189/table/t...

Mineral Content of Selected Commercially Available North American Bottled Waters: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1495189/table/t...

It depends where you live I think. Your tap water, if it's good, should normally contain a lot of minerals already. If you're drinking some kind of reverse-osmosis filtered water, then what you're saying makes total sense.

I lived in Cambodia for a while, where tap-water is a no go for drinking, and even though we avoided buying plastic bottles (plastic is a huge problem particularly in S.E. Asia) and instead stuck to larger tanks of filtered water, we had to make a point of always having some bottled mineral water in the mix. It was quickly noticeable when you hadn't had enough (extremely tired, drowsy, etc.)

If you want to get hydrated, you should drink water with approximately the same concentration of minerals as your body, especially if you lose a lot of water by sweating or sickness. Osmosis in your cells happens along the concentration gradient. Drinking water with too little concentration can cause them to swell, drinking water with too much can make them shrivel. Neither is good in the extreme.

Very interesting. I've felt this as well. Even bottled flat water, doesn't seem to hydrate me as well as a carbonated mineral water (e.g. Perrier or Pellegrino). I wonder if this is placebo or if there is some other meaningful effect happening.