I have a real curly one I'm going to throw out there to see if anyone has dealt with something similar. I am building a new dwelling out the back of my PPOR. There is no storm water and the planning permit has a condition that a pump pit has to be constructed to pump the water up to the curb. Currently the front dwellings storm water just tips into the ground at the rear!! This to now is not a big deal but how it gets tricky is that I need to subdivide and then sell the front property before I can build out the back. It makes no sense to construct this first as it will just get destroyed during construction. Now when it finally does get constructed I need something legally in place that will stipulate that the front property has its storm water re-directed into this pit. Clearly I don't want it just ripping into my back property around my foundations. Secondly I also want something in place which stipulates responsibility by both property owners for maintenance of the pump pit. Given that storm water will also be run into it. Note - There isn't common land so the pump will be within the boundary of the rear lot. Any ideas?