So the builder has come back to me today to say the council does not recommend soak wells due to the soil type (M5 class) and that we would need to use rainwater tanks instead. Details of the house / property:
Roof area (m2 on the flat): just under 400
Downpipes: 12 - 90x45 zinc
Location: South East Perth - foothills
Would a water tank (or multiple) be enough to handle storm water for this? The council would like to know the size of tank and location, anyone offer ideas on this? I would like it on the side where the proposed water tank is (below site plan), but if this does not work best for the height / fall of land etc then open to suggestions.