I work in a particularly longish office. I work at the front of the office and our water cooler is in the back of the office. I bring a 1 litre bottle and fill it up and make a point to refil my glass almost hourly.
It takes me approximately 60 steps from my office chair and back. Not a lot, but at least my chair isn't glued to my butt and I'm getting my required water intake for the day.