Building new house

Is it law that all new houses require a water tank installed, is there one rule across all councils as to what litre -age is required. Does anyone know what that is?
Nope, but I've hit the same thing - as well as a raft of other compulsary things you didn't need to get a year ago that add $11,000 total extra to the cost of building my house. Bit annoying as the house itself is only $84,000ish so that's a massive percentage extra.

And my builder doesn't supply the tank, just the connections. I'm getting a 27,000L tank Because I Can :cool:
Its an SA ruling for us. from July 2006, 1KL tank (so I'm going a bit above and beyond with a 27KL one :rolleyes: ) from July 2009 the hot water service thing came in.

5 star energy ratings have actually been in from 2006 so it must just be the water one that's making me think 2009.

From September this year new houses need a 6 star energy rating to comply. I have no idea if that is for houses signed for after september or what, but we'll be building right in that period. We're in a cold climate zone, same as the Adelaide hills so we have to have better insulation.
Was down the block yesterday and as there will be a bit of excavation to a hill back left of the block, my daugher suggested we get one of those flat tall ones that could be used as the retaining wall and cover it with trellis and creeper. We still have to get a building permit so the bldg insptr will know and probably will be designated on the full working drwgs when we get them. Want to go hell for leather on bldg this house so trying to do a bit of foreplanning.
I wouldn't use a tank as a retaining wall. They weigh nothing when they are empty. You still need solid stuff to actually retain the soil.
My understanding is that new homes built in Victoria require a rain water tank (for flushing toilets) or a solar hot water system. This is under the building regulations - achieving 5 star energy rating.

I'm not sure that there is any set minimum size, perhaps have a look at the Building Commission website or talk to a building surveyor.