Any fishwell, live well, storage box, or cooler built into a boat (which has a drain), will drain into a tube that is plumbed to a thru hull fitting. Generally speaking, I have never seen one that drains directly in to the bilge. Boat builders, as a rule, don't want water getting into a bilge on purpose. If you have on draining into a bilge, it was either modified or has something wrong with it. [links]