I had this dream a few months ago. I hadn't been swimming recently or anything. So, I live in a valley. There's a huge lake (Kootenay) and even from a sandy or pebble beach, it gets deep pretty fast. In the dream, I was at the lake. My husband was there, and he can swim pretty decent. My brother and my husband's cousin, Robbie (we hang out with him quite a bit when he's in town) were also there, and both of them are extremely good swimmers/divers. So, I was at the lake with them, and we were swimming against a rock wall so of course it was anywhere from 20-50ft. deep all along the wall. I was on a board (like a boogie board or something, we had two this Summer) on my stomach and the boys were just swimming. Suddenly, I slid backwards (feet-first) off the board. Now, I say I can't swim, but I can SURVIVE if I have to. I didn't even try to swim. Didn't yell for the boys to help me (and I realized, even in my dream, that they're all good strong swimmers) or anything. I just let myself sink. I kept my eyes open and looked up, and it was light above the water. Still didn't struggle at all to swim or call for help. The boys weren't even far from me or anything. I wasn't panicky or anyhting, it was totally calm. I just looked up out of the water, at the sun, and kept sinking. Suddenly, I couldn't see light any more. Everything went dark, and I woke up gasping for air, but still didn't feel panicky at all or anything, still totally calm. I didn't even think much of it when I woke up afterwards, just turned over, curled up with my husband and fell asleep again. Weird.
Usually water conotes our emotional state ("watery" eyes, crying wet tears, etc.) Your falling off the board probably means that you'll lose some support (say from a lover, husband, co-worker, parent, etc.). This is a time when most would become depressed and start to panic. If you do become depressed you'll probably do it consciously, not becoming identified with it (Buddhism belief, witnessing what's going on in your life without becoming involved.) You can probably expect a medium to long period of depression (sinking, light dimming). But now that you know that it is coming you will be prepared for it and so you won't panic. You know that you'll get through it because you were gasping for air afterwards, you know that you'll live through it.
DeathRowDisco, I thought being in water is about the time in the womb, and being aware of your spirit journey. And sinking deeper, it's like you're tapping into a deeper trust within yourself then, to feed and support your journey in this weird waking world with ( which sometimes takes your breath away). Just another thought
When I had the dream, as weird as it seemed, it kind-of made some sense. I had just lost my dad, my aunt and brother went home to Florida (my mom is the only other family I have here, the rest live in the States) and my best friend also went back (he was here for my wedding... my stepdad passed away three days after the wedding). It was a few weeks after the funeral, around the time that my brother went home, when I had the dream. So, it seemed to make sense... except, I didn't understand why I wouldn't struggle or call for help. But then, when I think about it, the people that I was with in the dream - my husband, his cousin and my brother - are people that I'm super close with and I trust them a lot. Maybe I just let go and figured they'd pull me out.