Vishwanath Srikantaiah is a water conservation expert who is renowned for his tireless and pioneering efforts to find solutions to the country’s freshwater crisis. Popularly known as Zenrainman on social media channels, his insightful articles on water and environmental issues frequently appear in mainstream news publications.

A Civil Engineer and Urban Planner by qualification, Vishwanath worked with Housing and Urban Development Corporation (HUDCO) for 14 years before dedicating himself full-time to solving water issues facing urban and rural communities. He is Trustee – Biome Environmental Trust, an organisation assisting communities in water and sanitation solutions; Director of Biome Environmental Solutions Pvt. Ltd., an architectural firm specializing in sustainable design; and an Adjunct Faculty at the Azim Premji University.

In a free-wheeling conversation with Ramya Coushik, Vishwanath demystifies water conservation and holds out hope for Bengaluru’s future with water.

All photographs courtesy Vishwanath Srikantaiah.

What triggered your interest in water conservation?

I began trying to figure out the rainfall patterns in Bengaluru in 1991. In 1994, when we started building our house, it was ironic that it was raining but we had to buy water for construction. So we devised the first rainwater harvesting system during the construction of our house.

The country is staring at a dire water crisis. How did we get here?

The defining period was 1991, when India liberalised its economy. The rapid and devastating impact on our natural resources began since liberalisation. One can clearly see that pre-1991, the pollution and destruction of our natural resources were not on a large scale, though dams were already being built, and the Green Revolution had unleashed the ‘High Yielding Variety’, which demanded much more water.

As an example, coal mining being expanded into forests through private companies is a direct fallout of liberalisation. The destruction of forests, and the sheer change in cropping patterns wholly geared towards an export market, came about after liberalisation. The aggressive overuse and abuse of our water resources and the use of groundwater technologies like deep borewells exploded.

This 7 – 7.5% growth of our economy comes with a proportionate 7.5% increase in water consumption year-on-year and a pollution-induced destruction of 7.5% of our water resources at the same time. So it is a double whammy.

What are your views on Bengaluru’s water woes? Is diverting water from rivers the only alternative?

Historically, Bengaluru’s graph with water has conformed to ‘Jevons Paradox’. Even with continuous capacity and governance enhancements, the city has always eventually outgrown all plans for water supply; and the demand has only compounded. The city gets 1450 Million Litres per Day (MLD) of water currently. But the situation is neither so drastic nor dire as to necessitate the diversion of water from rivers like Yettinahole or Sharavathi.

Bengaluru has four taps in its mix of water sources: rainwater, piped water, our lakes and groundwater, and treated wastewater. If we manage these efficiently, there is no need for any river diversion ever. There is enough to go around, if only the investments of money, resources and efforts flow to the right places. The city is drawing only 2% net from the Cauvery river, after returning 9% of the city’s water as treated wastewater for irrigation purposes to farmers in Kolar and other districts (discussed later in the interview).

A well fed by a shallow aquifer revived through rainwater harvesting and recharge.

With our ongoing well restoration and rejuvenation project–’A Million Wells for Bengaluru’–we can achieve 1450 MLD of water with just groundwater in order to support a population of 20 million projected for 2031. Cauvery river will supply 775 MLD more. 2225 MLD of water supply is therefore assured in order to support a population of 20 million at 100 Litres per Capita per Day (LPCD). Typical water supply designs for cities plan for 150 LPCD. When it rains, even without any interventions, we will get 250 MLD from groundwater sources. Our city is therefore not going to run out of water.

But in certain pockets of the city, people may have already run out of water or may not have water supply from Bangalore Water Supply and Sewerage Board (BWSSB). This is more a distribution problem. We should hence be focusing on ensuring that everybody gets a connection. The water available should be shared equitably, even if it is just 70 LPCD and not 100 LPCD. But it should never be the case of some receiving 200-250 LPCD and some getting no water at all.

The water scarcity in Bengaluru is therefore not a resource issue, but more a distribution issue. With 100 LPCD, just with groundwater and Cauvery water, which is now in place, we can support a population of 36 million, and not just the projected 20 million for 2031. We therefore do not need to divert waters from Yettinahole, Sharavathi or any other river. 

How does one apply equitable distribution to apartment complexes, especially the ones that house hundreds of flats in a single plot?

There are several measures that builders can take to avoid straining our water resources. Rather than issuing a blanket ban on new constructions, the government must enter into agreements with builders and get them to commit to investments in better resource management.

  • Water meters in every flat should be a bare minimum requirement in building guidelines and must be mandated by law.
  • Every building must compulsorily harvest rainwater. If a building has ground plus 19 floors, the harvested rainwater will last for only 60 days, but the water harvesting and subsequent usage should be systematic and efficient.
  • The builder should set up a wastewater treatment plant of the highest quality. A good example to cite would be the treatment plant at Cubbon Park, which treats its wastewater to drinking water standards. It should be run professionally by an external service provider and the builder should not just pass on that burden to the building residents’ association.
  • Buildings should plan for dual plumbing systems and all water for non-potable purposes should come from this treated wastewater.
  • It should be mandatory for apartment complexes to adopt a lake nearby and maintain it. This will ensure that the watershed is maintained, and whatever little groundwater recharge that happens benefits the neighbourhood.
  • There is also an urgent need to map the city’s underground aquifers. If the city has reliable aquifer maps, and if it is discovered during the foundation excavation that the groundwater source is good, the government should then permit the builder to put up stilted car parking above the ground and allow more Floor Space Index (FSI). This will ensure that there is no need for excavation, which may otherwise kill the precious aquifer beneath. The building should then recharge the aquifer and should have first rights over its usage. 
  • The government must assess water availability in the area before permitting buildings of ground plus 19 floors. In South Bengaluru, there is assured water. But in the north of the city, there is no groundwater. So the government must direct the growth of the city towards the south. 

Rain barrel – a simple rainwater harvesting system

If we understand our city, our aquifers, our FSI, our building by-laws, master plans, and our water in a holistic manner, we can become more water resilient, and a swimming pool at least should not be a matter of guilt within apartment complexes. We have turned water usage into a guilt-ridden experience. A human being is entitled to some luxury in life without being guilt-tripped.

Bengaluru is viewed as a monster gobbling up everything in its path to unbridled growth and using up valuable resources. How can the city give back to the state?

We need to remember that Bengaluru contributes to 60% of Karnataka’s GDP, and it is this GDP that is funding the state’s social, health and education sectors. So the city as a villain is a misplaced notion.

Bengaluru is already giving back in a wonderful way, in my opinion. 770 MLD of wastewater generated by the city is being given secondary treatment and supplied to Kolar, Chikkaballapur and Anekal districts to meet irrigation needs. The Kolar treatment plant pumps 270 MLD of treated wastewater to Lakshmisagara tank. It has now filled 19 tanks in the region, is recharging the groundwater streams, and farmers in the region are using the water for irrigation.

An aquifer-fed well used to irrigate a paddy field.

These farmers are reporting a 70 to 80% reduction in their use of fertilizers because this water is nutrient-rich. It isn’t only agriculture. Each one of these tanks can be imagined as a bird sanctuary like Ranganathittu. In the Kolar region, bird biodiversity is returning: leopards, deer and wild boars are returning because there is now water in the lakes. This is an excellent way of providing a link between the city and distressed-filled, drought-affected areas. Such compacts must be drawn by cities with its hinterland.

Bengaluru must also recognise that it is part of a river basin. It is the city’s responsibility to manage the forests of Kodagu and Kabini. 50% of the population of the Cauvery basin in Karnataka resides in the city of Bengaluru. It presently draws 6.67% of the Cauvery water, which is 1450 MLD, and plans to draw an additional 775 MLD soon. So eventually, in 3 years, Bengaluru will be using 11% of Karnataka’s allocation of Cauvery water. Bengaluru would have then grown to represent 60% of Karnataka’s population in the Cauvery basin.

Paddy fields irrigated with water from a restored groundwater aquifer.

The city uses 11% of the Cauvery water and returns 80% of that as treated wastewater. If this treated wastewater is provided to farmers, it goes back to the catchment, or the agricultural hinterlands.

Net, Bengaluru would have consumed just 2% of the water from the Cauvery for 60% of the state’s population. The city therefore need not feel guilty of tapping into River Cauvery. And because Bengaluru has the financial clout, it must take responsibility and make sure that the forests and springs in catchment areas are protected, and that there is no sand mining.

When we work with water, we should not let puritanism or absolutism dominate us.

Tell us more about your initiative – ‘A Million Wells for Bengaluru.’

The ‘Million Wells’ initiative is a facilitation of traditional well-diggers called ‘Mannu Vaddaru’, with the need to revive old water systems in the city. With everybody drilling borewells now, this community is out of jobs.

As per the state government’s rainwater harvesting policy, everybody is supposed to dig a recharge well. One must either build a sump or a recharge well. The bylaws state that the recharge wells should be a minimum of 10 feet deep. But if we dig up to 20 feet, we will be doing a far better job of recharging the rainwater. Bengaluru has 10,000 open wells. If we lead rainwater into a well and the aquifer conditions are satisfactory, the water table will come up and will be available for our use. Hence, we decided to target a million wells for Bengaluru.

If there is normal rainfall in Bengaluru, in a natural state, a mere 3-10% of the rainfall reaches the groundwater aquifers provided it is not built upon. This is despite Bengaluru receiving a good rainfall of 970 mm per year on an average. With lesser rainfall, the aquifer recharge further reduces.

An old well being cleaned and revived by Mannu Vaddars, traditional well diggers, under the Million Wells for Bengaluru project.

Therefore, the endeavour with rainwater harvesting and ‘A Million Wells’ is to not only mimic what would have naturally gone into the aquifers, but to augment it, and to take the groundwater recharge from between 3-10% to up to as high as 50-60%. That is equal to 1450 Million Litres per Day (MLD) of water in the aquifers, which is the same amount of water the city draws from the Cauvery river presently.

Once our wells are recharged, we should first use the water available in our wells. If we run out of water in our wells, have no rains and are faced with a drought, we can then utilise water from the Cauvery river to a certain extent.

Why utilise water from the Cauvery river even when we have good rains? Why can’t we let the river be for animals, birds and the river itself?  Why not create a Cauvery beneath the ground, in our wells? 

Once the groundwater table stabilises, there is a good chance that our lakes and springs will revive. So this is the goal of rainwater harvesting.

Our rivers should be clean, and our wells should have water so that rural India can learn to swim. Now our wells hold no water. Entire generations of young people in villages are robbed of this unquantifiable joy of jumping into a well and learning to swim with their buddies.

What kind of an impact can government and citizen-led afforestation programmes have on the water cycle?

New forests and new plantations consume water. Only the old forests can generate water. Our old forests have reached a stable state with hydrogeology (distribution and movement of water in soils and rocks within the earth’s crust or in underground aquifers) and rainfall. There are enough and more scientific studies that point to the fact that there is a steady maintenance of the hydrogeological aquifer levels in old forests.

A fast-growing new tree is water intensive. So there is no substitute for protecting our old forests. Deforestation has been the biggest threat to maintaining an overall ecological equilibrium. Afforestation can work only with healthy groundwater tables.

Jakkur Lake – revived with community and institutional co-operation.

What are some simple everyday habits citizens can cultivate to ensure better management of water?

As individuals, we should be keenly aware of our water sources.

  • We should make sure we have water-efficient fixtures in our houses, flats and wherever it matters, including in public places.
  • We should become aware of the food we consume, and its impact on our water resources. We should alter our diet appropriately, and shift to water-efficient produce. For example, avoid sugar as much as possible because sugarcane is a water-intensive crop. Avoid white parboiled rice and try to include more of millets in your diet. Be partial to seasonal and locally grown fruits and vegetables. Try not to fetishize apples and other produce not grown locally.
  • Be aware of what you send down the drain, especially chemical agents used in our homes such as detergents, soaps, toxic household cleaning solutions and antibiotics. Antibiotics are becoming a huge nuisance because they are ending up in sewage treatment plants and breeding super bugs. So be careful about the discharge let out from your homes to drains and sewage pipes. Send it to biomedical waste disposal places and not to water pipes.
  • Harvest rainwater. All you need is one small pipe fitted to the roof-top and one drum with a thin cloth tied on it. Let the filtered water into your existing sump that stores BWSSB-supplied water. It can be done in half a day with a plumber’s assistance and will just cost between Rs. 5000 and 6000. A 500-litre drum will fill up water 60 times from a 100 square metre roof and generate 30,000 litres of water.
  • Paints, thinners, oil and grease used in our vehicles should never be sent to storm drains. Find out if the place your vehicle is serviced in is managing such waste appropriately. There are service centres now that make sure that every drop of oil and grease is collected and reused. Such services are becoming available, and if they are not available, demand them from your service centre.
  • Get involved with your community and adopt a local lake or a local solid waste management plant. What we do with our solid waste is crucial to water, so segregate, recycle and compost, and persuade others to do it too.
  • Continue with what Emperor Ashoka said: plant trees wherever you can and conserve existing forests.
  • Finally, make yourself a nuisance to the government and get it to perform. Make your voice heard, demand better quality of water, better management of our sewage, and better management of our lakes.

If we do all of these in more and more numbers, things can only change for the better.

We have created a website: This contains a list of all the well-diggers, several water-related resources and case studies of some of the projects executed so far. We will eventually populate it with groundwater levels in various pockets of the city. Citizens can refer to it for information, guidance, and for simple resources to help solve individual and community water problems.