It’s all very well to plan a thousand square-foot garden with grass, trees, flowers, and vegetables. But, where will all the water come from to sustain them? My husband, Amit, who has been advocating water conservation strategies on his Facebook page worked with our architect on water conservation and reuse methods while building our home.
We had stayed in an apartment in Koramangala, Bangalore, for many years, and watched the water situation there go from having Cauvery water to borewell water, to tanker water, to being dry. Tanker water was bad for the hair, for one’s overall health (barely potable, even with a reverse osmosis filter), and rapidly becoming unaffordable. What was worse was living in an apartment complex, stuck with picking up the tab for everyone else’s water use or rather misuse. If one person in an apartment left the tap running and went to work, everyone’s taps would go dry. While constructing our house, we moved to an independent house nearby. For the first time, we learnt about sumps, pumps, automatic cut-off (and problems associated with the lack of it), the days and times when Cauvery water came and when it should have but didn’t, and the cost and hassle of calling a tanker when all else failed. We also learnt the joy of being largely independent as far as water was concerned.
That very independence would be our strength, in our new home, we decided. We planned our water system carefully. We were very careful with the way we used water, but in a rented accommodation, there is only so much you can do. In our new home, we selected taps and showers that consumed less water, and installed only dual flush systems. Amit also turned the water flow on all faucets down to less than half. Now, when you turn on a tap, you get a thin stream instead of a gushing deluge. All these measures combined to reduce our water consumption to about 250 litres a day. WHO standards recommend a consumption of not more than 70 litres a day, a standard most countries have not yet achieved.
We managed to keep our water consumption low, but what about supply? We had implemented rainwater harvesting — not just because it was mandated by law, but also because it was the source of good, drinking water, uncontaminated by anything except the dust on our terrace. We had built one main underground tank, which had a capacity of about 15,000 litres. This is not only filled by the Bangalore Water Supply and Sewerage Board (BWSSB), but also by the rainwater harvesting system. There is a pump, of course, that pumps water to the overhead tanks. Our next focus was on how we could conserve the water we were using?
Our architect suggested a grey water recycling system. Grey water is the water used in the house for washing purposes — excluding black water (what is used in toilets). We considered using grey water to flush toilets, but this looked like a complicated solution, involving a lot of piping. Also, by this time it was clear that we were going to have a vast garden, with a variety of plants and quite a bit of grass. The grey water could easily be used in the garden. But first, it has to be purified. For this, we used phytoremediation.
Phytoremediation makes use of specific plants, such as reeds that absorb the chemicals in grey water.
I have to admit, I was a bit sceptical about plants being able to absorb the chemicals. It appears they can. All the grey water in our house passes through the reed bed. The reeds are planted directly in the water; there is no soil above the water, just stones. When you run water into the drain, you can actually hear it gurgling through the reed bed. After passing through the reed bed, the water flows out into a grey water tank. This tank is covered with a fine metal mesh. Sunlight penetrates the mesh, allowing ultraviolet rays to further purify the water. We have a pump close to the grey water tank, to allow us to use this water for gardening. Not only is our garden flourishing with grey water, even the reeds are growing.
We don’t use grey water for our vegetables, though. Perhaps we could, but it didn’t feel quite right. So, at the back of our house, right next to the vegetable patch, we have a separate 5,000 litre tank, which is filled entirely by rainwater. This tank, which is quite deep, doesn’t have a pump. There’s a pulley and a bucket system, to allow you to draw the water. After all, there’s no harm in getting a bit of exercise, is there?
This year, the monsoon has not been good to us in Bangalore. All the same, our main tank in the front is full and so is our little tank in the back. We turned off the BWSSB water supply in April, when we started to receive the first pre-monsoon showers. All the water we have now is pure, clean rain water, accumulated over the past six months. Last year, after the last heavy rain in November or so, our stored rainwater lasted till the end of January. This year, we have more plants, so our water might last only till the end of December or so. We might have to rely on BWSSB for three or four months. The rest of the year, we use rainwater in the house and vegetable garden, and recycled grey water in the lawn.
The best part? The rainwater we collect is good water. We had it tested at a lab, and found that it was not just potable, but far cleaner than anything that comes out of a reverse osmosis system. We don’t even filter it; we just drink it straight from the tap.
This is the second of a five-part series about the green initiatives the writer has used for her home in Bangalore
