So, here’s your cheat sheet: 3 to 5 days for opened bottles in the fridge, 24 hours for room temperature, and never from a hot car after day one. Your mouth is the timer.
But let’s be honest—most of us will keep sipping until the bottle is empty, bacteria be damned. It’s the risk we take for hydration convenience. And hey, a little bacteria builds character.
Just don’t tell your doctor I said that.
