I used to hate water- it would make me gag to take a swig and if I had as much as a glass it would come back up again. Not nice!
I did though start to force myself to drink when I started to do more at the gym, mainly as I recognised feeling thirsty but had nothing to drink (I used to drink tea, pepsi max and diet lemonade). In the gym all they had were taps of water and a machine full of lucosade full sugar. I didn't want to drink full sugar stuff so I began to drink water.
It took a few months if not a year to get to the stage where I was drinking water all day. But now I think nothing of it. In a gym session I get through sometimes 2L of plain water (2 hr workouts) I don't even notice at times!
I'd say just drink when yu are thirsty, if you just don't feel thirsty, add in some water breaks, like a glass 3 times a day and build up from there. Another tip would be to drink little and often, fill a 500ml or 1L bottle of water and guzzle throughout the day. Aim to get through at least 500mls and eventually you will finish the bottle, just work on building up gradually.