An approach where a building or community uses only the water that falls on the site. Achieving Net Zero Water means limiting the consumption of water resources and preserving that region's resources throughout the year so that they are not depleted in quantity or quality. The aim of net zero water is to use alternative water sources (gray water, desalinated water, deposition systems, rainwater harvesting, etc.) to minimize the use of supplied fresh water and to preserve the quantity and quality of natural water resources by ensuring water efficiency.