Do you know how much you pay for water every month? Do you know how much you pay for your mobile phone every month? With these nonquestions, Ajit Gokhale, a rainwater harvesting expert, instantly hooks his visitor. Clouds of denial over the imminent crisis give way to sheepish acknowledgment that there is much more we could be doing to prevent Mumbai from drying up like Chennai.

“Our priorities are all wrong,” says the Dombivli-based waterman, who has been harvesting rain in innovative ways for the last 15 years. “We take water completely for granted. Unless you are living in the slums of Dharavi where you have to pay for every drum of water, you could hardly care where it’s coming from or how much of your society dues go into this.”

While new building projects post-2002 are required to install water-saving solutions in their projects – many of which blithely flout this rule – very few older buildings in Mumbai have introspected on how they can harvest water gainfully. When there is a shortfall, the tankerwallahs are invited, even as residents sigh about the dubious quality of the water. “In some cases, the managers of the building society have arrangements with the tanker companies which they don’t want to spoil with long-term solutions,” says Gokhale.

When there are water cuts, enthusiastic residents visit the civic corporation’s rain water harvesting cell (located at E Moses Road in Worli) which offers building societies a free consultation on how to harvest water, says a civic official. “The problem is that once they get the design, they have to wait for their AGMs to get approval. By then the monsoon happens, water is abundant, and everyone forgets,” he adds. “There is no data on how many buildings have implemented these systems.”

The basic principle of rain water harvesting is that you capture water before it drains out into the sea and either store it or allow it to seep into the ground to increase the rapidly depleting groundwater tables in the earth. It used to happen inadvertently but today, a formidable blanket of urban concrete leaves little scope for seepage.

There is no official data on the groundwater levels in Mumbai. The city is fed largely by water from lakes outside its limits by the municipal corporation. The Groundwater Surveys and Development Agency covers the rest of Maharashtra, where levels are going down at an alarming rate. However, anecdotal evidence suggests that levels in the city are also depleting.

Over 15 years, Gokhale has reached out to hundreds of housing societies with simple interventions that would help harvest water, increase groundwater tables or recycle grey bath water for use in flushes, for car washing and in gardens. He has mostly been met with indifference. And yet, several societies have risen to the occasion. Here are three case studies.

In Powai, rainwater harvesting

In Powai, the 3-block Sunshine Raheja Vihar had an open storm water drain running around it. The cost of building new pipes to harvest rainwater from the roof was formidable. So the flowing rain water was filtered with a system of sand and gravel and directed into the storm water drain for just over a lakh rupees. The bore well was soon meeting three months’ needs.

In Khar, greywater recycling

On 14th Road in Khar, a sevenstorey building, Gyan Ghar, invested in an infrastructure of pipes, filters and pumps which enables bath water to go through a series of simple bio-filterations through a reed bed system, to remove debris like hair and soap suds and make it clean enough to be pumped back up to be re-used in flushes.

In Andheri, groundwater recharging

St Catherines Home in Andheri used to have flooding during monsoon and scarcity in summer. After a simple method of allowing rainwater to enter the ground via a partially closed gutter, their bore well was replenished. The place did not flood even on July 26, 2005.

Many years ago, as a 10-yearold in Alibaug, Gokhale used to wonder how an island could have sweet water located inside it. His mother told him it is God’s work and he will find out when he grows up. About 18 years later, in a sacred grove called Kankeshwar, he had the epiphany and started his exploration, which culminated in reading the works of Anupam Mishra, the Gandhian environmentalist who believed India had enough water for everyone.

Gokhale looks at a Google map on his computer that takes a birds eye shot of a plot in Alibaug where he’d created a pond for a client and increased water levels in the well. The plot’s new owners have closed the water body for ‘vastu’ reasons. “Now that it has started raining, people will probably forget all about these issues and we will be back to square one,” he says.