The rule of thumb that I use is 1 litre/1000 calories expended. That takes into account activity level and not size and it closely matches water output. Of course in hot climates you sweat more and you need more water.
here's an article on water intoxication which is what happens if you drink too much water:
Also look up "hyponatremia"
Caffeine and alcohol are diuretics so they should not be counted fully as part of your water input. They can keep you hydrated though.
To answer your direct question, it does flush sodium out of your system so you may need to supplement to keep your electrolytes in balance. I don't think vitamins are an issue.
Try to match your input to your output. Your body will adjust retention and absorption to achieve balance. A good rule of thumb is that you should urinate 4 times a day and your urine should be light yellow.