Before using the Winterizing port to fill your freshwater tank, I would recommend flushing out that line first. Let it run out the shower hose for a minute or two first before connecting that hose to the freshwater fill port.
My reasoning is, sometimes people report smelly water. Sometimes it is the washer plumbing harboring stale water that can cause smelly water.
They fix the smelly water problem by flushing the washer plumbing.
When you sanitize your water system, how many remember to flush the washer plumbing?
(we don't have a washer so I installed shut off valves to the washer plumbing, so I don't have to winterize those lines).
How many flush the shower and Winterizing ports?
I'm guilty of that one.
We will be going dry camping in about a month to Ocracoke Island OBX NC. I'm going to flush that Winterizing and shower plumbing, next time I fill up (and every time there after) because we will probably need to refill the freshwater tank at least once while we are there.