I would drink and pea and wait until you stabilize. As cocoabeans points out, dehydration on lithium is the last thing you need. Drink to you heart's content! If your urine becomes complete colorless (without even a tint of yellow), notify your doctor. That could be a kidney problem. If you drink and drink and cannot drink enough, notify your doctor. But just regular 8 glasses of water a day should not be a problem (subtract your tea if you wish). I drink little water, but I drink roughly one cup of tea per hour, so it is more than 8 glasses a day, and I am fine.