through my many years (35 to be exact) I have witnessed a lot of people/co-workers swear by the whole drink 8 glasses of water a day.
I will admit, never tried it.
One thing i did try is the whole drinking hot water thing.
Rather a cup of tea, i would have a cup of plain hot water with a dash of lemon juice, i noticed that a poop more regular, that i felt generally better all round and that my skin was smoother.
I'd like to commit to drinking more water, but i'm a commitaphobe so its never going to happen.
tl;dr - if you can do it its good for you.