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 think you’re misunderstanding the tap water issue. Water isn’t stored for weeks or months in a water tank. It is cycled, generally filling up at night and being used throughout the day. Stagnant water in a distribution system is routinely checked for water quality to make sure it’s fresh and not that much different than what comes directly from a water treatment plant.