It depends on how you drink it, and how long it takes you to finish it. If you sip slowly and take like 1 hour to finish 1 cup, the pressure cannot be built up efficiently, so its going to take forever, also, the result would not be as ideal.
The ideal or "correct" way to intake it (whether its Epsom Salt solution, Olive Oil, distilled water or juice for cleansing) is to take big mouthful of it and swallow it, repeat doing so continously till it is finished... for people who do juice / water fast, take a mouthful of water/ juice, "chew" on it for awhile before swallow, this can ease the feeling of hunger.