Although it is good to be properly hydrated for a dive, there is actually no solid evidence that dehydration is as involved with DCS as many people seem to think it it. There is, in fact, a growing sense that the strong belief in the importance of hydration can lead to overhydration (water poisoning) and may be related to the rise in immersion pulmonary edema.I've been trying to focus a lot on hydration both before, during, and after diving. This is doubly true on multiple day trips.