Water reuse must move from the margins to the mainstream: Experts

Water reuse must move from the margins to the mainstream of urban water management if Indian cities are to address deepening water scarcity, experts and policymakers said at a day-long dialogue organised by WELL Labs in collaboration with the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and the Bangalore Apartments’ Federation (BAF).

Shift needed

Ram Prasath Manohar V., Chairman, Bangalore Water Supply and Sewerage Board (BWSSB), called for a fundamental shift in how cities think about water.

“Reuse of treated wastewater is no longer a peripheral environmental intervention. It is fast becoming the backbone of urban water security,” he said.

Noting that Bengaluru currently treats around 1,348.5 million litres of wastewater daily through 34 centralised sewage treatment plants, he said that if reliably reused, this volume can meet most of the city’s non-potable demand, while reducing pressure on rivers and groundwater.

Reuse, he noted, has already proven its value during the 2024 water crisis by buffering drought impacts and supporting environmental recovery. However, nearly 825 MLD of treated water is currently used for lake rejuvenation and for primitive usage in minor irrigation; Commercial and industrial reuse remains limited, underscoring the need for scaling decentralised systems with robust quality monitoring frameworks, Mr. Manohar said.

Integrated reuse grid

Mr. Manohar noted that the BWSSB is working towards an integrated reuse grid, similar to piped water networks, supported by reuse corridors, storage, booster infrastructure, and online monitoring. He further added that the BWSSB’s digital platform Jalasnehi enables users to book treated water online at rates of ₹10-20 a kilo litre, but sustained uptake from bulk consumers such as industry, construction, hospitality, and transport sectors is needed. Long-term offtake agreements can unlock private investment in pipelines, storage, and advanced treatment, he said.

Speaking at the event, Depinder Kapur, Head- Climate Centre for Cities, NIUA- drew on national studies of sewage treatment and reuse, noting that Karnataka and Delhi lead the country with reuse levels of 49% and 43% respectively.

He emphasised that Bengaluru’s political and institutional push to mainstream decentralised reuse offers a model for other Indian and global cities. He also called for the upcoming Liquid Waste Management Rules, 2025, to include enforceable targets and penalties to reduce freshwater demand through mandatory reuse.