Greetings BB 55 Bubble!
Tom is correct in that I too had problems with the exterior water entrances on both of my coaches. The Overlander needed a new city water entrance while the Minuet needed a new "gravity entrance" for the fresh water tank. Ace Fogdall handled the Minuet repair while Camping World handled the Overlander repair (this was before I discovered Fogdall's). In both cases, the original pot metal castings were of better quality than the new replacements, but the originals were just beyond repair. The "gravity entrance" for the Minuet is pictured below:
The City Water entrance on the Overlander is shown in the photo below:
Ace Fogdall RV lists a part that is very similar to the one in your photo in their current on-line catalog -- they don't give any dimensions that I could find in the on-line description but it may be worth some investigation. You can find the part at:
Good luck with your investigation!