The Decentralized Wastewater Treatment System (DEWATS) in Kuchpura, Agra, was developed by CURE through participatory planning in collaboration with the London Metropolitan University and Water Trust, UK. Kuchpura, a peri-urban low-income settlement, was bordered by a stormwater drain carrying untreated black water from the settlement and upstream areas directly into the Yamuna. To address this, a natural treatment system using gravity flow and bioremediation was introduced. The DEWATS comprised five chambers: a filter chamber for debris removal, a septic tank for primary treatment, a baffle reactor for secondary treatment, a reed bed system for tertiary purification, and an underground sump for storage. Capable of treating 50 kiloliters of wastewater daily, the system not only reduced BOD levels before discharge into the river but also enabled residents to reuse treated water for construction, urban agriculture, and non-potable needs—encouraging a shift from sewage-based to clean-water farming. As the first of its kind in Agra and Uttar Pradesh, the DEWATS served as a replicable model of ecological slum development. It improved community health, increased land values, and spurred housing renewal. Recognized as a Best Practice by MoHUA, the project also informed the design of the Taj East Drain Improvement Plan, highlighting its broader influence on sustainable urban water management.