The Brihanmumbai Municipal Corporation’s (BMC) latest move of cutting down water supply to new buildings might have left several Mumbaiites into a tizzy, but rainwater harvesting can be the answer to the impending water crisis for builders and residents. In fact, many in realty business admit the move may force builders to adopt the green route.

In rainwater harvesting, the rainwater that falls on rooftops is collected and stored in tanks, trenches, borewells, etc. In 2002, the BMC had made it mandatory for the new buildings having a plot area of 1,000 square meters to have rainwater harvesting facility. By 2007, the same provision became mandatory to buildings having a plot area of 300 square meters and above.

By that notion, the civic officials state, all the new constructions should invariably have this facility. However, the BMC statistics reveal a very low figure. According to the records available at the civic body’s rainwater harvesting cell, till 2007 only 171 new buildings have adopted the facility.

The BMC maintains that both awareness campaigns and stricter rules have proved futile. “Since 2002 we have adopted a stricter rule in this regards. Any building proposal is cleared only when they have made facilities for this (rainwater harvesting) technique. Otherwise, the occupational certificate (OC) is not given to the builder,” said assistant engineer of BMC’s rainwater harvesting cell, Suprabha Marathe.

But the real problem, Marathe says, is that many builders have the facility only symbolically. “Sometimes builders have the plan on paper but they never implement it. There are three different entities when it comes to any building —builder, architects and residents. Though the onus lies on the builder to implement the facility, unfortunately occupants are of the law and never question the builder,” Marathe said.

The main problem the BMC faces is in implementing and monitoring the law properly, she says. “In other cities, rainwater harvesting has succeeded immensely as the residents hold the builders answerable. This makes even their municipal bodies to take active participation. Unless, we have an active monitoring body, the rule will never be successful in the city,” Marathe said.

Keeping in mind the mushrooming constructions in the suburbs, the BMC has decided to cut down the supply of water from the present 90 litres to 45 litres per person per day. This is also for only those buildings whose demand is less than 2 lakh litres per day.

However, many builders believe BMC’s new decision will compel builders to take the green route. Suresh Gadekar, project manager of the Supreme Builders which is coming up with a seven-floor building in Charkop, says: “We have installed an open terrace rainwater-harvesting system. We have also installed storm water drains and percolation tanks on the ground. These facilities will help the residents here deal with water shortage.” Gadekar adds that “the BMC’s decision will force many builders to adopt “green” construction. Praful Kanajoia, manager, Kalapataru Properties, which has residential and retail projects coming up in Kandivili, Andheri and Thane, says they installed the facility in all their buildings even before the civic body came up with the rule. “We have installed borewells and underground rainwater tanks in all our buildings. Considering the looming water crisis, this is the only way to properly utilise and save BMC-supplied water,” Kanajoia said.

Meanwhile, BMC also plans to go ahead with retrofitting projects in existing buildings. “We are asking old and existing societies to adopt rainwater harvesting. Though many people are yet to warm up to the idea, the cost factor is also a major deterrent. They don’t realise money is only spent in the initial stage. Despite our best efforts to spread awareness, people still have reservations,” said Marathe.

Environmentalists also opine that rainwater harvesting is a feasible option. “With rainwater harvesting underground water can be easily pumped. Also since our city gets good monsoon, this is a good way to utilise the rainwater. Moreover, it also helps in reducing flooding remarkably,” said Vishal Bhanushali, an engineer with Eureka Forbes Institute of environment.