Drinking loads of water isn't necessarily healthy. Be guided by the colour of your urine. Ideally it should be a pale yellow. If it is clear, then reduce the amount of water a bit.
Too MUCH water can deplete your body of electrolytes and that can have serious consequences.
There is no ideal fluid intake, but if you exercise or live in a hot place, then you will need more. If you eat a lot of foods in a soup/casserole-type format, then odds are you won't need so much to drink. Some medications require you to drink more. Some health conditions require you to drink less (renal issues for one)
Below is a link written by SP's own well-qualified experts that you may find helpful: www.sparkpeople.com/community/ask_the_expe