Studying the New York sewage system from the building scale to the urban scale, we have analyzed the problems and proposed a site for each experimental wastewater treatment plant. Hydro-Flow is located in the Upper East Side, which is the most congested multi-family area and uses the most water. This area has had toxic contaminant problems released to the East River for many years due to inadequate treatment. Accordingly, hydroponics treatment has been introduced to apply green technology for experimental wastewater treatment and benefit the community by integrating space with an organic farming market and a common playground. The design concept has been developed from a system structure of water pipes and hydroponic rails that are linked into one system. Through the form of piping construction, we can use the architecture itself to communicate and learn the process of water treatment. The aim of Hydro-flow is not purely focused on bringing clean water to the community but also on creating a new public space, allowing for interaction within the neighborhood through space, program, and educational experiences. This relationship will eventually give the opportunity for the community to be part of the wastewater treatment plant.