It's salt water, and it's not coming from the ice box.
How do you know? Did you taste it? EEeeehhhh!
Like stated above, the packing gland is supposed to drip so many drops a minute. But also, if you're taking water over the bow, the chain locker drains to the bilge. 1/2 cup of water is nothing. Careful not to tighten the packing gland too much, could cause friction heat.