Allow, educate, and encourage households to use greywater
In many countries, grey water is used by households and other buildings to collect run-off from roofs, washing machines, sinks, and bathtubs to water gardens and flush toilets.
Allow and encourage people to install alternative plumbing systems to make this possible. In Australia, there is an entire sector of the plumbing industry dedicated to installing and maintaining these systems.
Included in the Draft Greenest City Action Plan.