Doesn't seem to have a number, but just check your local hardware store in the garden hose fittings.
This Gilmour is the best one I found.
The other thing we've found is when you stay put camping, you will have to add water. Then, of course you eventually smell gray water as it burps out the vents in the tank. We drain off a few gallons into a milk jug and go dump it in the ocean or whatever is convenient.
Adding water: collapsible water jug or collapsible 50' hose. Pictures below.
Hope this helps. Jim