Hi feebal, if yu choose to cut out the water if you feel that whats causing the heartburn then please make sure you keep up your fluids in other ways. Ideally you should be drinking 2-3 litres a day. I suffered terribly from heartburn, moreso with my 2nd pregnancy. I was precribed gaviscon advanced as I found gaviscon (original and double action) to be useless. I also would have to keep myself propped up during the night as laying down would immediately start it off. Another thing is to little and often. Instead of three main meals, try 5 little meals.
ILS, good luck with your final weeks, although I dont think they will take you in early unless baby was in any distress. They were quite happy to let me keep going on 3-4 hours sleep a night, and thats with a 7 yr old to look after too! The only good thing about it was that it prepared me for the sleepless nights! lol Even seeing to a baby 2-3 times a night, I was getting more sleep than I was when I was pregnant!