Bengaluru has faced a severe water shortage in recent weeks, forcing residents of large apartments and gated communities to buy costly water tankers for daily use.
Interestingly, Metropolis Gurukrupa, an apartment complex, is doing fairly well. Until the summer of 2018, its residents would also buy tanker water like most of Bengaluru, causing them additional expenses.
Resident Ganesh Shanbhag took matters into his own hands and decided to tap a readily available source—rainwater—to provide a steady water supply for his apartment.
Initially, many residents were reluctant as they were under the impression that installing a Rainwater Harvesting (RWH) system is expensive. This led to him taking up the project by himself along with other like‑minded residents.
“Using a rain gauge, we noticed that the city received 1,300 mm of rainfall that year, which is sufficient for 80 percent of the city’s needs. But with large areas rapidly being concreted, rainwater seeps into sewers,” he says.
He informs that residential complexes with more than 40 houses are mandated to have an RWH and sewage treatment system.
Ganesh noticed that many other complexes were using pop‑up filters, which incurred a high operating cost for setting up the rainwater harvesting system
Once he was sure about its working, he procured necessary raw materials such as pipes and disc filters over pop‑up filters to reduce the operating cost.
“The only difference between the two is that pop‑up filters require extensive maintenance, while disc filters require manual cleaning. This means there is zero operating cost if done by residents,” he adds.
Ganesh mapped out routes to channel the water from the terrace to four underground tanks with a capacity of 50,000 litres each. The tank was fitted with a pressure pump that took the water to the overhead tank.
If all four tanks were up to their capacity, the excess water was allowed to overflow into a recharge pit, which channels the water into the ground thereby increasing the groundwater levels.
Ganesh says, “Residents now spend Rs 1 lakh a month on water tankers, but our rainwater harvesting system meets our water needs for seven months a year.”
Although he doesn’t charge any money for the work, it costs about Rs 3 lakh to purchase necessary raw materials.
“I consider this a hobby, and would like to work with other apartments who have faced water crises and want to implement this,” he adds.
So far, more than 200 apartment complexes in Bengaluru have adopted Ganesh’s RWH system, and continue to reap the benefits.