The summer of 2024 brought severe water shortages to Bengaluru, one of the worst in recent memory. Headlines across the country highlighted the city’s struggles with insufficient water supply, dried-up borewells, and skyrocketing water tanker prices. Given the urgency of this crisis, it’s high time to explore research-backed solutions. Bengaluru, situated on a hill, lacks its own independent water source. The older parts of the city rely heavily on water pumped from the Cauvery River basin, while the newer areas depend on independent bore wells. 

Over the last two decades, as Bengaluru’s reputation as the Silicon Valley of India grew, its population doubled, the urban sprawl expanded, and its green cover diminished significantly. As a result, the demand for fresh water has far outpaced supply.

Water scarcity is not only a pressing health concern but also a critical factor influencing the economic development of the city. 

Lakes are drying up, and in some areas, groundwater levels have plummeted to unprecedented depths. ​“The deficit in the water supply system, coupled with rising water demand, has created a significant gap leading to water shortage,” says Ram Prasath Manohar, IAS, Chairman of the Bengaluru Water Supply and Sewerage Board (BWSSB). To address this crisis, proper planning, education, and resource management are imperative. Bengaluru Science and Technology Cluster (BeST), under the initiative of the Office to Principle Scientific Advisor (OPSA) to the Government of India (GOI), has recently undertaken an analysis of Bengaluru’s water crisis.

Addressing Bengaluru’s water woes

To address the pressing water crisis, BeST convened a panel of experts, drawing from government agencies, scientists and researchers studying town planning and water treatment technologies, start-ups, non-profit organisations, and citizen representatives from Bengaluru. The diverse group addressed challenges and proposed an actionable plan to mitigate the situation. The panel identified four major problems contributing to the water crisis:

• Rapid population growth leading to increased freshwater demand
• Urban Planning and land use leading to suboptimal usage of water resources 
• Climate change and erratic rainfall patterns
• Overexploitation of water resources and insufficient recycling efforts

In response, the panel proposed a strategy aimed at reducing Bengaluru’s dependence on water from the Cauvery River by enhancing local water recharging and reuse systems to achieve ​“net-zero water” for the city. Rather than relying solely on the Cauvery as the primary water source, the experts recommended an integrated urban water management plan. This approach emphasises recharging groundwater, expanding rainwater harvesting capacities, rejuvenating lakes, and significantly increasing water recycling. Vishawanath S, Director of Biome Environmental Solutions, says,

Implementing these measures could greatly alleviate Bengaluru’s water woes.

Recharging groundwater

The fast developing metropolis is undergoing innumerable constructions every day. Fields and open lands are being cleared to make way for housing layouts, which in turn are depleting the city’s natural water catchment areas. Prashanth Palanisamy, from GoodEarth, a sustainable building solutions start-up, suggests that conducting basic hydrogeological studies to assess groundwater levels before construction could help identify water catchment areas (aquifers). Planning constructions around these areas would allow for faster groundwater recharge.

Another method to recharge groundwater is by constructing community borewells near aquifers, rather than having individual borewells for separate houses. Bengaluru receives abundant rainfall, with an average of 800 – 1000mm per year. With a better understanding of its water catchment areas, the city can better equip to handle harsh summers. Rejuvenating surface water bodies like lakes and ponds also plays a crucial role in groundwater recharge. 

A success story is the rejuvenation of Sarakki Lake near J P Nagar, which led to a significant increase in groundwater levels within a year. 

Over the last three years, the water table around the lake has significantly improved. T V Ramachandra, Professor at the Indian Institute of Science (IISc), claims that maintaining groundwater levels is key to solving Bengaluru’s water crisis. 

Wastewater treatment and recycling

According to a recent news article, Bengaluru is home to one of the highest number of sewage treatment plants (STPs) in the country, with nearly 2,644 in operation. However, despite this large number, the city struggles to recycle most of its water due to poor management and financial constraints. Sanjiv Sambandan, Professor at IISc and co-founder of Openwater, a start-up specialising in innovative waste treatment solutions, highlights that the economics of recycled water remain unclear. Sambandan observes, ​“The common man does not see the financial benefits of wastewater recycling”. 

Vishwanath also points out that a lack of funding often leaves STPs non-functional. Bengaluru’s decentralised STP system has the potential to set a strong example for other cities, but only if it can effectively operate and utilise recycled water. Vishwanath suggests that​“a modest increase in water rates” could help cover the financial needs to keep STPs running. Engaging communities, developing frameworks and policies for wastewater treatment, and partnering with existing technologies like Openwater could also address this problem. Additionally, ensuring that apartment complexes have functional STPs is another critical recommendation raised by the committee. BeST has partnered with the Bangalore Apartment Federation to help their member apartments assess the situation, equip them with efficient technologies and train their STP operators.

Functional rainwater harvest treatment plants 

Climate change has significantly impacted Bengaluru’s weather patterns. Vishwanath explains that the city now experiences a sinusoidal rainfall pattern, with alternating cycles of abundance and scarcity in rain. This inconsistency makes addressing the water crisis problem even more challenging. Moreover, water scarcity typically only becomes severe during the two summer months, causing many citizens to downplay the seriousness of the issue. As a result, only a small portion of the population truly understands the importance of rainwater harvesting.

While rainwater harvesting is mandatory for all buildings, its actual implementation is often left unchecked. Many houses lack proper filtration systems to utilise harvested water, and more than half of the population lets rainwater flow straight into the drains. In some cases, space limitations are a concern, while in others, issues of reliability, functionality, and cost deter people from implementing rainwater harvesting systems. As a result, much of the abundant rainfall goes to waste. Although there is no scientific solution to ensure effective rainwater harvesting, experts agree that raising awareness is the key to making progress.

Water management is a straightforward equation: we can either buy water or invest in recharging it. 

The cost of purchasing water during peak demand is significantly higher than the investment required for recharge systems. In the long run, prioritising efforts towards water recharge and achieving ​“net-zero” water will provide a more sustainable and economical solution to the problem. Apart from this, raising citizen awareness and promoting the responsible use of water are crucial steps toward conserving our precious water resources.