The use of the water hyacinth plant for wastewater treatment is considered a simple technology that does not require costly machines or equipments, a large labor force, or complex maintenance processes. It requires only large areas of land and a hot climate. In view of the renewed interest on utilization of unconventional water resources, including wastewater, and the desire for reduced environmental contamination at surface water sources, the possibility of applying this technology is being studied. Its application is particularly important in scattered rural areas with small residential communities, to prevent the spread of disease, and to help preserve the natural beauty of villages and rural areas.