Enough water for 3-4 months for Bengaluru, says BWSSB; experts call for long-term measures

As the erratic southwest monsoon continues in Karnataka for the second consecutive month, Bengaluru continues to reel under a dry spell. According to the cumulative rainfall data for the city from June 1 to July 9, Bengaluru Urban has recorded a -35% departure from normal, while South Interior Karnataka recorded -24%. The scenario has raised fears of the impact on power and water availability.

Even though the Bangalore Water Supply and Sewerage Board (BWSSB) has reintroduced water conservation norms it brought in during the monsoon season itself this time compared to the water crisis of the summer of 2024, Manjula N., chairperson, BWSSB, maintained that there is no reason to panic for now.

Current consumption

“At present, Bengaluru is drawing around 1,900 MLD of Cauvery water every day, while we still have an additional 300 MLD of available capacity that can be drawn if required. With Cauvery V Stage, the total amount of water available is 2,225 MLD. Therefore, there is no shortage of Cauvery water supply to the city,” she said.

She, however, admitted that the challenges being experienced in certain localities are primarily due to groundwater depletion and dependence on borewells, as well as distribution-related issues.

“I recently held a review meeting with the concerned officials managing the Cauvery reservoirs and assessed the current storage position. Based on the available reservoir levels, even if there is no rainfall over the next three to four months, Bengaluru’s drinking water requirements can be comfortably managed through the Cauvery system. However, there will be stress in the later months in case there is absolutely no rainfall,” Ms. Manjula said.

She also pointed out that inflows into the KRS reservoir have already started improving, which is an encouraging sign. “BWSSB is continuously monitoring reservoir levels, demand patterns, and groundwater conditions on a real-time basis and is fully prepared to take necessary measures wherever localised water stress is reported. Citizens need not panic. We appeal to everyone to continue using water judiciously and avoid wastage. Water conservation remains essential, but there is no cause for concern regarding Cauvery water availability for Bengaluru at present,” she reiterated.

Water security

However, yet another year of erratic weather patterns has triggered the question of long-term water security for Bengaluru. Priyanka Jamwal, Senior Fellow and Convenor, Ashoka Trust for Research in Ecology and the Environment, said erratic rainfall patterns directly affect urban water security by increasing uncertainty in both surface water and groundwater availability.

“For a city like Bengaluru, this means greater dependence on tanker water, especially during periods of delayed or deficient rainfall. The burden is felt most sharply by vulnerable communities, who often have limited access to reliable piped water and end up paying much more for basic water needs. Erratic rainfall also affects rural and peri-urban regions that supply water to the city. Groundwater depletion in these areas can affect agriculture and may push people to shift from farming to other income sources,” she said.

She also pointed to public health risks posed by tanker water sourced from borewells, many of which are located near lake beds or close to lake peripheries and have the possibility of being contaminated by sewage, industrial wastewater, or polluted stormwater flows.

Has much changed since the 2024 crisis? Ms. Jamwal said there is now greater public awareness about water circularity, decentralised wastewater treatment, and reuse of treated wastewater for non-potable purposes.

“Many apartment communities, especially high-rise residential complexes, are treating and reusing wastewater for flushing, gardening, and other non-potable uses to reduce dependence on freshwater sources,” she explained.

“There is also more attention on reducing losses within the water-supply system. Efforts are being made to address pipe leakages, water theft, and non-revenue water. These are important because improving efficiency in the existing system can reduce pressure on new water sources,” she added.

She said another positive change is the increased collaboration between government agencies such as BWSSB, GBA, the Climate Change Cell, civil-society organisations, researchers, and local communities and said such partnerships are important because water scarcity cannot be addressed only through large infrastructure projects. However, she said these changes need to be scaled up and institutionalised.

T.V. Ramachandra from the Indian Institute of Science also pointed out that vital resources for the city, including water, come from the Western Ghats and climate changes in the Cauvery basin directly affects the city. “Bengaluru also depends on groundwater to an extent of 45% of the total demand. However, the transition from porous to paved landscapes has prevented percolation and consequent groundwater recharge,” he said. 

Circularity needed

Ms. Jamwal stressed on the need for groundwater regulation. “Since groundwater is often treated as a free resource, many communities prefer to extract groundwater rather than invest in treated wastewater reuse, which can be more expensive. Research also shows that treated wastewater reuse becomes economically viable mainly in larger residential communities, especially those with more than 300 households and those that are already dependent on tanker water for meeting domestic demand,” she said. The long-term solutions must include mechanisms to regulate groundwater extraction and clear policy guidelines for treated wastewater reuse, she added.

“Bengaluru also needs to move towards a circular water model. The city receives water from the Cauvery, uses it, and generates large volumes of wastewater. Bengaluru should treat this wastewater to a high standard and make it available for safe reuse, including irrigation in peri-urban areas,” she said.