Why will water start to taste bad when you leave it in a glass for too long, but will taste fine when you dispense it out of a tap where it’s been sitting for months?

Question

If you leave water in a ceramic, glass, or cup it will start to taste bad after a day or two, even if it’s covered with a lid. However, when we pour water out of a tap into a glass it will taste fine, even though it’s been sitting for days/months in a water reserve tank. Why is this the case?

In: Other

Answer 1

I can’t really answer the question but I want to point out that this might just be your personal taste preference.

I think the water that comes out of a tap to taste gross. I taste the minerals and dislike it. I like to drink filtered water. In my experience, filtered water that had been sitting out for days in my water bottle taste just fine. I don’t leave water sitting around in cups for days but I’ve drank water that was in a cup from 1 day ago and taste fine.

I also don’t think water that “sits for months in a reserve tank” is comparable to sitting in a cup. Large bodies of water have current flow. The water in that reserve tank is still moving around constantly, way more than the water is moving around in a cup.

Also unless you have a reserve tank in your house, your tap water came from the pipes that came from a water treatment facility – with pipe connections to thousands of other houses. The water is constantly flowing through the pipes and not “sitting around”.