A rain garden is a water-saving garden that is designed to capture stormwater from hard surfaces such as driveways, patios and roofs via downpipes after it rains. Read more: Melbourne Water Encourages Australian Citizens to Build Rain Gardens
vertical gardening could incorporate fish water to sustain plants & both to sustain you. Plants clean fish water returning re oxygenated & clean to sustain fish. All it requires is management as we are supposed to do with creation.