If you winterized with antifreeze, you should winterize that connection as well. First, relieve the pressure on the line by opening a faucet. Go outside, remove that city water screen, and GENTLY press on the valve center until antifreeze comes out. Reinsert screen.
Just be careful when you GENTLY press in on the valve, because it can easily be thrown out of whack and leak. (and if you do, I'll post instructions for you to fix it...just say the word)
Pete (Jolly Mon)
2014 Jayco Whitehawk 24 RBS
2004 Nissan Titan LE, 4x4