What amount water can i drink before getting general anesthesia?

You could: drink a glass of water two hours before general anesthesia.

Timing is important!: It's not so much the amount, it's the timing. Some hospitals are very strict about nothing by mouth for 6-8 hours. Others will let you drink water up to 2-4 hours before surgery. Check with your hospital or surgery center about their policy. Do not eat any solid food after midnight or 6-8 hours before surgery. Clear liquids OK espcially if you need to take your meds, but nothing within 2 hours.