Through a series of fortunate events, Hotel DiuWak became a testing ground for a project led by engineer Maritza Marín from a Central American NGO (ASEPESA) looking to install biogardens in rural communities. Biogardens process and treat gray and soapy water and allows its reutilization. Grey water comes from the laundry, showers, hand basins, dishwashing and other domestic uses.

In Hotel DiuWak´s case, seven shallow long ditches were dug, river stones placed at each end,  rocks in the middle and submerged lilies and heliconias. Amazingly, the roots of these plants fulfill a natural chemical process which purifies the water, which then drains into the local river without contamination.

Initially built in the mid 2000´s, the project was so successful, the National University of Costa Rica studied its results for three years, its Chemistry department analyzing samples monthly. Overall, the water´s purity tested at 80-90%, and does not pollute the environment. The Hotel DiuWak is the only hotel in Costa Rica that purifies 100% of its black, grey and soapy waters through its 7 artificial biogardens.