Rainwater Harvesting has been a talk-of-the-town for many years now, particularly in a country where we get to see extreme instances of rainfall. Within the State of Maharashtra, the coastal regions including Mumbai, the Western Ghats and Konkan regions, the rainfall witnessed is way beyond the national average. Mumbai, especially, is the city with the highest recorded annual rainfall in the whole country. Yet, the eastern parts of the state like Vidharbha, are prone to draughts; where farmers commit suicide, residents lack an access to drinking water, and local industries suffer because they do not have the most basic of the resources.

The Government of Maharashtra has sporadically paid attention to this issue, which has not yet sufficed. Though, the BMC has implemented some very stringent guidelines regarding rainwater harvesting for construction within Mumbai. Mumbai heavily relies upon its lakes and brooks for providing freshwater. Monsoon showers help these lakes to recharge but this, solely, is not enough to supply water needs of tens of millions of residents of Mumbai. Some basic rainwater harvesting techniques are aimed at taking off some burden from BMC in terms of non-consumable water unlike the drinking and cooking water.

The BMC guidelines state:

1) Construction of an underground tank which would suitably collect all the rainfall in the precincts of the building.

2) Connecting the sky-facing surfaces, like terraces, pavements et al, with the tank, preferably with a filter to block away from the debris.

3) A passage from the tank into the depth of land in order to recharge groundwater levels when the tank is full, further connecting the pit with the submersible borewell to extract that water when needed.

All these guidelines are pertaining to a set standard of measurement, where the requirements increase in a proportion to the increase in the area of construction. These guidelines are also amendable in a case where the proposed regulation poses a threat to the strength of the structure of the building, where any leakage or dampness in the foundation would be fatal.

The BMC has also taken into account the conceivable rainwater harvesting in the public works. It ensures there are proper channels to direct the rainwater from bridges, tunnels and other public arenas to nearby reservoirs. When these reservoirs reach an almost full capacity, the authority pumps out the extra water into the sea. Here, we believe, we lack in our engineering capabilities. Mumbai and its authorities flush out ample of water which would be enough to supply into all the slum-dwellings, instead, it could look into amplifying its ability to effectively relocate the rainwater.