I agree with the WHAT WAS not the fix but the problem
I have been cold weather camping not entierly by plan for some winters now Even in S.E. GA we had freezing nights (not many) and where I am now we get many ONLY twice have I had an issue
ONce I had a "Y" adapter on the park spigot that broke due to freezing (Minor problem < 10 bucks) and the other tine I did not PERSONALY have an issue but the park did so I could not tank up when I wanted to (Minor issue got water at next stop an hour later. No danger)
WHat I do is this: I tank up. then drain hose and disconnect it. Now if the park freezes.> Well that's their problem I have at least 30 gallosn on board (normally) if I can not re-tank here well the other park is the same water system so no problems.. Normally I only hook up in the park I'm at and for OTHER REASONS I tank up and use only tanked water.. If there is danger of freezing I disconnect and drain the hose. Other wise I leave it connected and tank up again before I leave. the other park I do a "Short setup" no hoses just power.