Bengaluru: Despite unveiling plans in March to pipe treated water from apartments to lakes and industries, BWSSB is yet to make headway in turning wastewater reuse into an environmental and economic success story. Apartment federations said pilot tenders to connect 20 lakes are still in early stages, while builders continue to rely heavily on fresh water. Gautam Kamath, board member of Change Makers of Kanakapura, said: “Even after using treated water for flushing and gardening, around 40% remains unused, which goes up to nearly 60% during monsoon. There are no takers even when it’s offered free. The BWSSB’s app-based sale system is yet to take off,” he said. Some apartments have struck independent arrangements with nearby parks or industries to use surplus water. At Sobha Garnet apartments in Iblur, an underground pipeline carries treated water to adjoining park. “Our STP produces about 20,000 litres of treated water a day. We use around 6,000 litres for gardening and send the rest to the park,” said KG Mohan, former association member. Lake link progress In Feb 2025, BWSSB floated tenders to supply treated water from apartment sewage treatment plants (STPs) to lakes in south Bengaluru. The plan included laying 200mm pipelines to fill lakes such as Gottigere, Kammanahalli, Begur, and Yelenahalli. Sewerage board officials said they have begun linking nearby apartment complexes to lakes for supplying excess treated water from their STPs. So far, 14 lakes have been identified for the project, including Kothanur, Chunchagatta, Begur and Ganapatipura. “The work is already underway and nearing completion. We will launch the project in the coming weeks,” Manohar said. “We want to build demand — if not for lakes, at least for use by govt bodies in parks, BMTC or KSRTC depots, and the construction sector. Unless we create market demand, industries won’t even know this option exists,” Bangalore Apartments Federation (BAF) president Satish Mallya said. Cost hurdle for buildersBuilders agree treated wastewater could ease city’s water stress, but cite logistical barriers. “If treated water is available at construction sites, many builders will use it,” said Suresh Hari, vice-president of CREDAI Bengaluru. “But transportation costs remain a major challenge. The best approach is to use it close to the source.”BWSSB is already using treated water from its central STPs to fill 23 lakes, with another 17 under way. It said over 8,900 million litres (ML) of treated water have been used to revive Jakkur, Yele Mallappa Chetti Kere, Kengeri and Madivala lakes and another 2,737 ML will be used for lakes now being rejuvenated, including Chikka Bellandur and Dorekere. With Bengaluru drawing about 2,225 ML daily from Cauvery and 1,000 ML daily from borewells, civic experts say expanding decentralised reuse could significantly reduce pressure on the city’s fragile groundwater reserves.
