There are no Water Monitors indiginous to Australia (with the exception of Merten's, but I'm sure that's not what you're looking for
).
I assume you're meaning Aussie Water Dragon?
If you are looking for a monitor that is small, easy to handle, doesn't bite and makes a great pet.......well, that's the recipe for an Ackie (aka - Spiny-tailed Monitor). Check out Varanus.net and read the FAQ there to learn more about Monitor husbandry.
I would also be happy to aide you in anyway I can as well.
Best wishes,