* * * drinkable * *. Medical stone can purify water. Unless the cup is well insulated, 12 hours usually won't make the water too cold. If so, the water is drinkable.
* * * Not drinkable * *. If the cup is well insulated, 12 hours may make the water temperature very low, even reaching freezing point. If so, water should not be drunk, because ice water may cause gastrointestinal problems.
In a word, the remaining water in 12 hour can't be drunk, which mainly depends on the thermal insulation effect of the water cup and the ambient temperature. It is recommended to check the water temperature before drinking to ensure that it is suitable for drinking. At the same time, in order to avoid potential health risks, it is not recommended to store water in any type of cups for a long time.