Hey Guys,
Well the filler tube for my fresh water tank showed up and as many of you guessed, I was able to confirm that it IS a drain for the fresh water tank.
The second water was put in, it came out. So, I ordered a Pex valve for it which should be here any day.
As for why it's dripping, I opened up my plumbing cabinet and there is some sort of cross over in the system and that seems to be how water is making its way into the fresh water tank.
I'm to sure if it was designed this way, or if the previous owner decided to plumb the pump into the City water feed.
Thanks for the help!!