Bengaluru’s real estate developers are turning to advanced recycling systems to collect, treat, and reuse wastewater from households, as the city’s worsening water crisis increases dependence on private tankers. Leading players such as Brigade, Prestige, Puravankara, and Assetz Property Group have turned to advanced greywater recycling systems. They have introduced dual and triple plumbing systems in large residential and commercial projects, going beyond regulatory mandates of the Bangalore Water Supply and Sewerage Board (BWSSB) and Karnataka State Pollution Control Board (KSPCB). “We are taking it one notch higher with dual plumbing as well as converting post treated water into domestic use in a couple of our newer projects with the intention of standardising it across our portfolio in the near future,” said Roshin Mathew, executive director & head-engineering, Brigade Group. “Given this, nearly 100 percent of our projects will be reusing treated grey water to the best possible level.” Prestige Group also said 100 percent of its large residential, retail, commercial and mixed-use projects in Bengaluru now integrate greywater recycling and reuse systems. “Three to five years ago, while most large projects had sewage treatment plants (STPs) to comply with regulations, reuse was partial, limited to gardens or flushing. Full integration of dual plumbing and cooling reuse has become standard across all new large projects,” said Nirbhay Lumde, senior vice president (ESG & sustainability), Prestige Group. Puravankara reported a nearly four-fold rise in recycled water use, from 400 kilolitres in FY23 to 1,950 kilolitres in FY24. Assetz Property Group said water savings in its large-scale projects have reached up to 86 percent through triple plumbing and extended rainwater harvesting. Regulation, demand, and costs While regulatory pressure remains key, developers pointed to rising consumer awareness. “The good news is that we are seeing an increase in buyer awareness and inquiry into future availability of water,” Mathew said. Lumde added that compliance remains the baseline but customers in water-scarce areas increasingly favour projects that reduce tanker dependence. “Customer awareness is steadily growing, and people today understand that freshwater is a scarce resource which will become more expensive in the coming days,” Puravankara CEO (South) Mallanna Sasalu said. These systems, however, come at a cost. Mathew said segregated treatment plants cost around 40 percent more than combined plants because of construction complexity, equipment requirements and higher energy use. Buyers in select projects have agreed to share the additional expense when long-term benefits were explained. Sasalu said operations of STPs cost Rs 30–35 lakh annually, given the need for reverse osmosis membranes and skilled maintenance, though such systems enhance project credibility. Lumde said “buyers increasingly consider water security a premium feature, especially in Bengaluru, where the fresh water supply is stretched”. Challenges ahead Despite wider adoption, developers say scaling remains difficult. Concerns include maintaining water quality, managing dual plumbing networks, the expense of retrofitting older projects, and shortages of trained operators. “Lack of awareness among customers about using recycled water beyond flushing and low levels of acceptability are challenges. The time is right for introducing a national policy for urban wastewater reuse,” Sasalu said. A greywater recycling system collects, treats, and reuses wastewater from household activities such as bathing and washing clothes. This process makes the water suitable for non-drinking purposes such as flushing toilets, irrigation, and washing vehicles, which helps reduce the demand for fresh water.