When the residents of TZED Homes, a community in Whitefield, faced water shortages, they did not immediately resort to using tanker water. Instead, they opted for an unconventional solution — treating and reusing wastewater for potable purposes. It was a difficult decision, and even more challenging to convince all community members to accept.
“Until four to five years ago, we could access water at a depth of just 80 feet. However, tankers extracting water from commercial borewells have significantly affected our aquifer,” says Babu, a resident closely involved in water management in the community. But, their efforts have paid off — TZED Homes now meets 80% of its water needs without relying on external sources. It remains the only housing community in the city to implement tertiary wastewater treatment for potable use.
As Bengaluru’s groundwater levels continue to decline, a few communities in the city are adopting sustainable and innovative approaches to achieve water self-sufficiency and reduce environmental impact. Some are using recharge wells, while others have implemented rainwater harvesting (RWH) systems. Here, we explore a few of these initiatives.
Sustainable urban living
So, how did TZED Homes become water sufficient? Spread across five acres with 90 homes, the community uses different approaches for water conservation — rainwater harvesting, reverse osmosis (RO) of treated water and much more. “We have a rainwater harvesting sump with a capacity of four lakh litres, which can meet more than a week’s water needs,” says Babu. “We harvest rainwater and utilise it to its fullest potential.” In a year with ideal rainfall, TZED Homes can sustain itself entirely on rainwater for up to six months.
Recharging groundwater
The community also has 40 recharge pits, each 20–30 feet deep, and open wells to facilitate aquifer recharge. Every drop of rainwater is either stored or sent into the ground, unless there is flooding.
Read more: For home-buyers in Bengaluru, a checklist to assess water security
Turning wastewater to drinking water
Another highlight is its tertiary sewage treatment plant, which recycles wastewater and the RO system that purifies treated water for potable use. Even the RO reject is used for gardening, car washing, and recharging the aquifer, thus completing a sustainable water loop. Weekly water quality tests ensure safety, and residents are promptly informed of any drop in standards — a key factor in building trust over time.
“Regular water quality checks helped us convince people. However, some residents and new tenants are cautious and have installed their own RO systems at home,” adds Babu.
The community treats around 45 kilolitres of sewage daily, yielding approximately 40–42 kilolitres of reusable water. This reduces their monthly expenses by roughly ₹1.8 lakh.
Despite having a robust system, the residents have occasionally faced challenges. They had to rely on tanker water briefly in 2019, and again in 2021 and 2022, mainly due to over-extraction from commercial borewells supplying tankers. “Since the water scarcity in 2023, we still need tankers, but only for about 20% of our requirements,” says Babu. “We are trying to be completely water-neutral and self-sufficient for all our water needs.”
Babu points out that effective water recharge must become mandatory for all households and communities to avoid scarcity in the future.
The community also documents all knowledge and practices related to water management. New residents are routinely educated to maintain and further improve the systems in place.
Refusing to depend on Cauvery water, Babu explains, “Neighbouring areas receive Cauvery supply just once or twice a week. When you factor in the pro rata charges and the bribes often involved, it would be cost-effective to run our STP instead for a few years.”
Also read: Water management: What Bengaluru can learn from towns like Devanahalli
A housing layout with heritage wells
While new technologies help achieve water security, sometimes traditional wisdom and age-old solutions can be just as effective. One residential community, for instance, relies on a classic solution — heritage wells. “Our well has never been dry in the last 13 years,” says Jyothi Saundatti, a resident of Classic Orchards.
A decade ago, three old heritage wells were restored. “We cleaned them by removing almost 100 tractor loads of silt, which was reused for developing vegetation,” says Chockalingam Muthiah, a resident. These open wells, connected to the clubhouse, have remained a reliable water source.
Spread over 71 acres with around 350 homes, the Classic Orchards residential community has implemented robust rainwater harvesting, treated wastewater reuse and groundwater conservation to fulfil its water needs. Starting with just five to six recharge wells 13 years ago, today, around 100 recharge wells collect rainwater within the layout.
Scientific solutions
A scientific study conducted in partnership with Biome Trust helped the community understand water requirements, topography and existing infrastructure to plan the location of these wells. This helped ensure maximum recharge despite the challenges of already-laid roads, drainage pipes and other structures.
Treated water is reused for gardening, car washing and construction work. “Now, treated water is also being used by newer homes for flushing, although initially it wasn’t mandatory for older houses and we did not have dual piping,” says Chockalingam.
Being self-reliant
The community does not rely on tankers for non-potable needs. Individual houses use Cauvery water for potable purposes, and a few houses maintain their open wells. Common borewells, drilled to 200 feet, are reserved for emergency use, such as extreme water scarcity or STP breakdowns. “We try to manage all the needs without relying on groundwater, a common resource,” says Jyothi.
The efficient system prevents 35 lakh litres of sewage from going to waste every year by treating and reusing it to meet all the layout’s water requirements. Rainwater harvesting alone contributes about 276 kilolitres annually, and 100% of the treated wastewater is reused, significantly reducing stress on the Cauvery water supply.
“In the next 2–3 years, we anticipate the need for a second STP or an upgrade to our existing one to handle future demand. The system has remained cost-effective despite operational expenses, thanks to the residents’ commitment,” adds Chockalingam.
Beyond infrastructure, regular awareness campaigns are conducted for residents on reducing water consumption, using safe cleaning agents, and preventing construction material runoff into drains. With around 3,000 trees spread across the layout, the community not only secures its water needs but also promotes climate resilience and a cooler microclimate.
Recharge wells in informal settlements
While large housing layouts often have access to facilities, the reality is different in informal settlements. Munnekolalu in Bengaluru, home to around 2,000 families, is one such area. Most residents here earn their livelihoods through waste picking, domestic work, and similar occupations. The lack of proper housing, drainage, water supply, and sanitation infrastructure worsens the impact of urban flooding on residents. To address this, Hasiru Dala, a social impact organisation, installed recharge wells to manage surface runoff, enhance groundwater recharge, and reduce flooding.
Moreover, the Hasiru Mane Initiative, a housing programme under Hasiru Dala, focuses on providing affordable and sustainable public housing solutions for waste picker communities.
Hasiru Dala identified recharge wells and open wells as viable solutions to alleviate waterlogging during heavy rains and improve groundwater recharge. Ramakrishna, from the well diggers community, facilitated the construction of the wells. Two recharge wells in Munnekolalu and Belagere were constructed by Hasiru Dala.
It’s been only about six months since the recharge wells were installed, and there hasn’t been significant rainfall since. “These communities depend on either tanker water or groundwater accessed by the landowner, who also charges them for it. So, having a recharge pit will help raise groundwater levels while also reducing flooding,” says Sowmya Sridhar, Assistant Programme Manager, Hasiru Mane Initiative.
RWH a challenge in public housing complexes
In addition to recharge wells, Hasiru Dala installed rainwater harvesting at Kuntigrama, in October last year, where public housing was established. “Though it was challenging to install an RWH system, we managed to do the piping work and store the water in drums, which the community uses for non-potable purposes,” adds Sowmya.
Initiatives like this can significantly strengthen the resilience of vulnerable communities. By enabling access to local water sources through recharge wells, open wells and rainwater harvesting systems, they help reduce the reliance on tanker water and landowners.
As Bengaluru grapples with growing water stress, scaling such community-led models could pave the way for a more sustainable and equitable water future.
Key learnings
- Rainwater harvesting is the simplest yet significant part of sustainable water management.
- Apart from storage, it is also important that rainwater is recharged into the ground, which could help in times of scarcity.
- Closed-loop systems can significantly reduce the dependence on external water sources.
- Hasiru Dala’s initiatives demonstrate that water solutions can also be implemented in low-resource communities.
- STP systems in large communities and apartments can save several lakhs of rupees each month.