:) i had a nightmare a few days ago, again with that tiled walls, deep and blue and i just thought am i the only person with this fear? it couldn't be! then i google it and i found this website. this "overwhelmed" theory seams to be near the answer... at least for me.
I also didn't have a bad episode in or near a pool that i can remember. and some time ago i totaly freaked out when i was with a friend getting some money from an atm machine in a glazed building and as i took a look thru the glass i saw there was a pool inside, it was full of water, but still, as i wasn't expecting it and it was dark and noone inside, i just couldn't control myself despite the embarassment, i run to the other side of the street, tears poping out of my eyes, my heart beating so fast!
i think i'm also kind of afraid of the tiles and also i have problems with other places with enclosed water, like dams or so.
Nice to know i'm not alone. If you find more about this subject, please just post it in here :)