One major reason to buy commercially bottled water is that it tends to store safely at room temperature more/less indefinitely. Tap water in many places is not

One major reason to buy commercially bottled water is that it tends to store safely at room temperature more/less indefinitely. Tap water in many places is not sufficiently chlorinated to safely store long-term. For what it's worth, I think the standards for basically all drinking water, including municipal supplies, are pretty low. Accepted levels of arsenic in ground and tap water (and probably some bottled water) are calibrated to a shockingly high tolerance for causing cancer, well above the typical target risk of one in a million.