I got the drip pan emptied, found out the problem is the water line that connects to the filter housing is leaking, can that line be replaced in a whirlpool side by side refrigerator? Should I also replace the filter housing?

Show us a picture.

Which one is leaking? You may just need to replace a fitting on the water line. You do not need to replace the filter housing unless there is a crack in it, and that would be very rare.