Hey I usually drink at least one gallon of plain water a day while on beastdrol. Then there is 1/2 gallon of milk, plus your water for pre/NO drinks, and if you drink a intra-training drink also.
As much as you can is best. Somedays it's hard to get it down, but if you just chug for 5-6 seconds at a time, you can get through it pretty quick instead of sips.
I did a cycle of beast with a friend, and he didn't do the water thing. Kept with coffee, milk, diet soda's. He was working out good, and his diet was "ok" other than the lack of water. He didn't gain hardly anything. IMO I blame the lack of water.
mike