Constructed and natural wetlands are being utilized for water quality management of a broad variety of wastewater types worldwide. While water treatment is a primary goal of many of these systems, there is a general recognition that ancillary benefits for public use and wildlife habitat are typical of some of these wetlands. Also, there are growing numbers of constructed wetlands that are primarily focused on providing habitat and/or public use while relying on pretreated wastewater as the principal water supply. Efforts are currently underway to document the normal ranges of human and wildlife use benefits of treatment wetlands, and to provide a reasoned assessment of the potential environmental risks associated with these systems. Information collected from existing surface-flow treatment wetlands indicates consistent net benefits for wildlife habitat and public use. An understanding of the relationship between design and operation of treatment wetlands, and their positive and negative ecological and societal responses, will allow for optimization of new wetland systems.