The interconnecting hose issue in Tas was mentioned above. In the huge Hawkesbury fires in the 90's, I was in SA and we sent a convoy of fire appliances to help. They were sent out to fires but found they couldn't connect to the hydrants, each state had a different system, so they wasted a lot of time scouring hardware stores.
I had a fire at work, we already had a hose set up from the hydrant and security sent a nozzle which wouldn't fit - SA nozzle on NSW hose! A small fire became a conflagration
I believe that the situation has been rectified but I can't confirm that. I hope so as we had fire equipment from other states here in Vic
BS from M