BENGALURU: In a significant move to conserve water and reduce reliance on the Cauvery River, the Bangalore Water Supply and Sewerage Board (BWSSB) has announced plans to make greywater recycling mandatory for all newly constructed buildings and detached homes in the city. A detailed policy framework is being developed and will be submitted for government approval by the year’s end.
Currently, the requirement for wastewater treatment and reuse applies only to apartment complexes with over 120 units. However, given Bengaluru’s rapidly increasing population and frequent water shortages due to climate change, officials believe expanding this mandate to individual residences is essential. Experts support this initiative, asserting that greywater reuse will alleviate the city’s growing reliance on freshwater sources and ease the strain on the existing drainage system.
Presently, BWSSB expends thousands of crores to pump 2,225 million liters of Cauvery water daily from approximately 100 km away. Alarmingly, about 40% of this treated water is allocated to non-essential uses and ultimately wasted, often draining into underground systems and overburdening the sewer network. Officials assert that recycling greywater — the used water from kitchens, bathrooms, washing machines, and sinks — could substantially reduce wastage, diminish the load on drainage pipes, and lower the city’s dependency on Cauvery water by 40-50%, while also aiding groundwater recharge.
A senior BWSSB official indicated that the new regulation will initially target new constructions, as implementing it for existing homes poses challenges. “We aim to introduce this policy in phases, starting with new buildings and detached houses. A comprehensive set of guidelines will be developed and submitted to the government shortly,” the official stated.
Understanding Greywater Recycling
Greywater is the wastewater generated from kitchens, bathrooms, dishwashing, and laundry, excluding toilet waste. Currently, this water flows directly into the city’s drainage system. The new policy will mandate builders to install distinct pipelines for greywater and blackwater (toilet waste). Greywater will be collected in a separate tank, treated, and reused for applications like gardening, toilet flushing, and cleaning.
To ensure efficiency, households must prevent soap wrappers, plastics, and solids from entering the system. Separate soak pits or filters will be constructed to purify greywater, with regular cleaning mandated at least once annually to maintain groundwater quality and hygiene. Dr. Ram Prasath Manohar stated, “The move to make greywater recycling obligatory for new constructions is a progressive step towards securing Bengaluru’s water future. Once finalized, the policy framework will be sent to the state government for approval.” If executed properly, this initiative could be a significant milestone in Bengaluru’s sustainable urban water management journey.
