Aim for a higher percentage in water leaks. 15% reduction is NOT enough - put more in doing this to prevent water wastage. This should be your main aim but as it is a cost to you, no utility company wants to do this. It does not help your return to shareholders but is benefit to all other parties.
Reduce groundwater reliance - put more into the reservoir build.
Lobby the Government to resurrect the 1976 plan for a national water grid.