Fire System to save property during major bushfires

People put there lives at risk to defend their property from the onslaught of a bushfire.
My idea to fire proof property is with the use of water pump and dedicated water tank. You set up a series of spray sprinklers on the roof and under the eaves. 
When a fire approaches you start the pump and the spray sprinklers wet down you roof and gutters, thus stopping flying embers catching your house on fire. The water running into the gutters will flow back into the tank giving a prolon...