:hijack:
Yes the hot water is on a seperate meter normally. I can only talk about QLD, not sure about the other states.
It all depends on the size of your house and the hot water system.
There are normally 3 tariffs available to wire an electrical circuit into when you build your house. (adding an extra meter later could be expensive)
Tariff 11 (on all the time) - generally only used for normal power, aircons you don't want to go off or a very small hot water system. About 15c/kWh
Tariff 33 (controlled supply, on most of the time, only off at peak times) - used for "permanently connected" pool pumps, aircons, washing machines, freezers. About 9c/kWh
Tariff 31(night rate, usually only on from about 10pm to 7am) - used for large hot water systems, must be 250 litres or bigger. About 6c/kWh