Wetland functions are physical, chemical, and biological processes or attributes that are vital to the wetland system. Wetlands are transitory zones between different aquatic zones and therefore, wetlands have a profound biological impact. Wetlands function as an export for organic materials and as a sort of sinkhole for inorganic materials.

Wetlands also provide habitats for several types of organisms. They might contain the last of a rare species or an endangered species.

Wetland systems also can absorb a large amount of water. This allows them to protect shorelines, help to remove pollutants, prevent floods, and this is why they are known as the "kidneys of the landscape."