BMC’s plans of rainwater harvesting washed away

As Mumbaiites continue to grapple with water shortage and the monsoon still a couple of months away, the civic body’s decade-old plan to make rainwater harvesting systems mandatory for new buildings could have been a saviour. For a city, which has been reeling under a 20% cut in water supply, the water generated through rainwater harvesting could have been used for all non-potable purposes.

Almost a decade after the Brihanmumbai Municipal Corporation (BMC) made it mandatory for new buildings in the city to have their own rainwater harvesting systems, only one-thirds have installed it.

The civic body supplies 3,750 million liters per day (MLD) of water to the city, while Mumbai’s requirement is 4,200 MLD. The water shortage this year has led to the supply dropping to 3,200 MLD.

Between June 2007 and December 2015, 1,848 new buildings have got the systems on their premises. But, according to BMC estimates, at least 5,000 new constructions were approved during the same period. It means, only 36% of the new buildings have followed the norms.

What’s worse: The civic body has no mechanism to find out how many of the 1,848 buildings (residential/commercial) actually use the rainwater harvesting system.

According to experts, ensuring that rainwater harvesting systems are installed by new residential and commercial buildings and by encouraging others to set them up, the BMC could help the city tide over the water shortage to some extent. Significantly, the BMC would not even have to spend any of its funds for these projects.

Every time there is a water shortage situation owing to deficient rainfall, the civic body insists on making rainwater harvesting mandatory for new projects, but fails to implement it. In 2002, the BMC had made it mandatory for all new constructions above 1,000 square metres to install rainwater harvesting system to obtain their occupation certificate (OC). In 2007, this rule was extended to buildings over 300 square metres.

There is no provision for action against developers and house owners for not complying with the rule. The civic body can only put their OCs on hold. This, however, is not a deterrent since the developers and house owners still sell or rent the premises without an OC.

It is also observed that projects built in prime real estate areas do not comply with the rainwater harvesting rule. According to data from the BMC, the compliance is highest in M ward, which includes Chembur, Govandi and Mankhurd. More than 200 new buildings have rainwater harvesting system in these areas. However, wards such as A and C, both in the island city — where real estate prices are among the highest in India – do not even have a single building with rainwater harvesting system.

A 2013 study by think-tank Observer Research Foundation (ORF) states that even if half of a developed area on a building’s rooftop is utilised for rainwater harvesting, around 590 million litres of water could be generated every day. Dhaval Desai, a research fellow from ORF, Mumbai, said athough the BMC has mandated rainwater harvesting, it does not have any institutional mechanism to check for compliance. “The rainwater harvesting department in BMC exists only on paper. It has got no executive powers. No builder can be penalised for not implementing the system,” said Desai. “Most of the societies [1,848 that have the system installed] would not have bothered to maintain the system too.”

Senior civic officials, however, look at the issue differently. “The law is already quite stringent and many buildings are complying. To improve water supply, the big game changer will be treating sewage water by setting up plants in the next three years,” said civic chief Ajoy Mehta, adding that it would provide the city with 50% more water.

Citizens, however, feel rainwater harvesting is the best long-term solution for the eight months when the city does not get rain. Monisha Narke, who has setup the system in her building at Mahim, said: “The BMC can make it more stringent for the builder and withhold all clearances till the system is setup. The system is a long-term solution for using water for non-potable purposes.”

First Published: Apr 06, 2016 00:52 IST