How long can miralax (polyethylene glycol) safely last in water before you drink it?

Taste vs safety: I don't believe polyethylene glycol (miralax) gets spoiled and so there is no time limit for it to be in water for use--it is in GoLytely for many months/years. The powder form probably won't taste as pleasant leaving in the water too long--as it is a osmotic agent and this sucks-in water and can thicken a bit over time. Enojy it while it is fresh :-) consult doc. Good luck.