I struggle with the water too, I've tried everything. I used to have a 2litre bottle which I carried around all day at work, but it just seemed like too much to drink, then I tried a litre bottle, but by lunch time I'd get sick. So now, what I do is fill 2 500ml bottles before I go to work. I drink 1 on the way to work, then I have 1 before I start work. I then refill them, have 1 at 10ish, and the other at lunch time. Refill them again, have 1 at 3ish then 1on way home... 3 litres of water gone, and I haven't even noticed. It's much easier.
I also find drinking water at room temp much easier than having cold water. It's taken me a long time to work out this routine, but I stick to it and it works fantastically. Then on an evening if I'm thirsty I just have a glass or two and that way I'm not dashing to the loo in the night either. xxx