Welcome to FT
fredylee
Yes SQ certainly uses bottled water. I find they tend to hand out the bottles more freely on the ultra longhauls (between SIN and LAX or EWR) than on other routes. However if they dont hand out early in the flight, just ask (say you want a large bottle) and there will be no problems getting it.
Your wife will probably want row 22 aisle seat. Easiest to get in and out of and reasonable space. The drawback is less pocket space (the pocket on bulkhead isnt as big or convenient as those on seatbacks.
Enjoy your flight(s).