Hi ! Welcome to IRV2! We're sure glad you joined us!
From your description of the problem, it seems to me that it would be the connection of the line to the water valve. I would try a new compression-type clamp and see what happens.
Good luck, happy trails, and God bless!
Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD