We have been advised by our builder that the City of Wanneroo (our shire) do not require soakwells to be installed. Having done a quick google I'm not coming up with anything to contradict this (next stop, call the council). If they confirm that we don't actually HAVE to have them installed, then we face the question of SHOULD we have them installed (our builder will not let us do them ourselves as apparently they are liable if something subsequently goes wrong).
I understand what they are for and that to work out the size it depends on your roof sqm, but what I don't know is whether we need them on our plot - it's a sandy plot, no clay / soil but don't know what to do next!
Thanks everyone