Yes, but nowadays we have water via a pipeline, and as everyone is saying, the main cost is not the water, it's other charges. We also have a full house dam courtesy of a wet Summer. I think I'd need to pick my spot very carefully - protect them from hot north winds - and keep an eye on them, but then same can be said for the Crinum, also Hippeastrums and Frangipanis I'm growing.
I would love to see photo's of your Salvias. They're great, aren't they? Love the aroma when you just brush against one like Salvia Hot Lips. We would have a similar climate, with California and Victoria (my state) being the two most bushfire prone places on the planet.