alot of people look at water as a bad thing, but it isn't.
if your pre- contest , a high sodium high/ high water intake is a blessing as it keeps you full.
if your are looking to rid yourself of water for cosmetic reasons, you can try a couple of things without going the chemical route and see how that goes for you.
green tea extract and dandelion root are natural diuretics that will help you avoid taxing your liver/ kidneys that you may using other compounds.
that being said pre-contest i will normally use arimidex thru my prep, but i honestly wouldn't suggest anything other than a natural approach for ridding yourself of unwanted water if it is just an annoyance or for cosmetic reasons as said before.
i know of some guys who will use lasix on weekends if they are bulking to help them rid themselves of water retained thru the week from running androgens and a high carb diet/ sodium intake. but these are guys not doing it to look good on the beach.
so, all i can say is determine why you want to lose the water, and then take the necessary apporach to remedy the situation using the least taxing compounds available as a means to remedy your water issues.
hope this helps.
BFU