A Call for Permeable Paving

with permeable paving, stormwater doesn't all become surface runoff

With permeable paving, all stormwater doesn’t become surface runoff
Image Source: Flickr

I’ve said it before and I’ll say it again: urban dwellers have an obsession with paving every possible open space.

Housing society compound?
Pave it — we need to park our cars!

Open area where social interactions take place?
Pave it — our clothes get muddy!

Barely-used internal road?
Pave it — we get stuck in the monsoon and it’s hell on the tyres!

If we Must Pave, Let it be Permeable

Some of this paving may well be justified but, because it is done indiscriminately, it leads to a boatload of problems related to the water table, the health of the city’s trees and even the heat we’re subjected to. I’ve written all this in greater detail elsewhere on this site but this particular post is about a type of product that could help in such situations.

In late 2015, there was a buzz in the construction world as Lafarge UK showcased a super-porous asphalt that could guzzle an incredible 4000 litres of water in about a minute. Media started calling it “thirsty concrete” and truly, if you watch the video below, it does look like the water is vanishing into desert sands.

Permeable Concrete Video

I have never been a great fan of the wasteful use of concrete but, when it is required, the least we can do as architects is to try and use it correctly.  Unfortunately, at least as far as I can tell, this product and others like it are not readily available in India. In fact the only case I know of permeable concrete being used, is for a parking lot at Jaipur railway station.

Unless architects and engineers specify such products and create a market for them, there is no way that companies will manufacture them here. I do hope some of my brethren in the industry take up the call.

Reduce Hard Paving

In our urban environment we see numerous examples of open spaces with hard paving all over them. One of the reasons for this is our insatiable hunger for parking. The earth in our cities is starved of air and water — sacrificed at the altar of our rubber-shod tin cans.

“Ah”, but I hear you say, “we really do need that parking space!”.

Of course, if our city fathers were more enlightened and aimed for better public transportation instead of caving in to the cult of the car, we wouldn’t have reached this impasse in the first place. However, this page is not a rant about ineffective urban planning but about the effects of indiscriminate paving and what we can do about it.

When we pave over open spaces, a number of things happen.

The Water Table Drops Dramatically

This one is pretty obvious and hardly needs an explanation. If the ground is paved, there is no way that any more than a tiny fraction of rainwater will ever reach the soil. In Bombay, there was a time when one could dig a well and hit water not far below the surface. These days, the only reliable wells are the ones that adjoin large green spaces — like the maidans for example.

Other cities are not so lucky and those who live where borewells are common will tell you that the wells need to be dug deeper every year. The water they reach is also an increasingly fickle seam. The demand on the groundwater is constantly on the rise but all that paving never allows it to get recharged.

Egress of Saline Water in Coastal Areas

too much paving leads to a drop in the water table which allows egress of saltwater

Freshwater is lighter than saline water

Saltwater is denser than freshwater and forces its way inland below the latter. If the (fresh) water table drops, the boundary between them is pushed deeper inland. Salinity in the soil is not merely bad for plant life but also for construction.

Trees Find it Difficult to Survive

For plants — and especially trees — paving is doubly detrimental. Not only is there very little water in the soil to help them grow but their roots are also unable to breathe. As a result, the trees develop a weak rooting system; it is no wonder so many of them topple over during the monsoons. That many of the avenue trees in our cities are fast-growing exotics, doesn’t help very much either.

Drainage Systems are Overwhelmed

Kalyan Station under water July 2005

Kalyan Station under water
Image source: Wikipedia

When it rains in an urban area that is excessively paved, the runoff has to go somewhere! That somewhere, is the storm-water system which is frequently unable to cope. This leads to the all-too-familiar floods we see every year.

At best, flooding is an inconvenience but, as the last few years have shown us, it can also be deadly. Corrupt builders, politicians, and bureaucrats are responsible for the rampant encroachment on natural drainage channels in many of our cities. This results in the kind of devastation and loss of life we saw in Bombay (2005), and Madras (2015).

No doubt, in both cases there had been uncommonly heavy rainfall. We must remember, however, that climate change is causing an increased frequency of such extreme events, so it would be foolish to brush them aside as a freak events.

Worsening of the Urban Heat Island Effect

urban heat island

Temperatures are significantly higher in cities
Image source: Wikipedia

Paving is one of the major factors leading to the heat island effect — that phenomenon where an urban area is significantly hotter than its surroundings.

Unlike soil which cools off rapidly when the sun goes down, paving retains heat for longer and then emits it slowly through the night. One of the only ways to reduce this effect is to increase the area under plantation (including on roof terraces). However, as we have seen earlier, that is rather hard to do, when everything has been paved over. It’s a bit of a vicious cycle.

What We Need to do

Of course the very best thing to do is to avoid paving as far as possible. However, there are many situations when we really have no choice. At such times, the least we can do is to use materials and systems to mitigate the problems we cause.

Pervious Concrete Paving

permeable concrete

Permeable Concrete
Image Soure: Wikipedia

This is a type of concrete where the fine aggregate (sand) is missing so that the concrete becomes porous enough for water to percolate through. This means, of course, that it is not as solid as other concretes and cannot sustain the same heavy-duty usage. On the other hand, it is perfectly usable in areas where traffic density is low or, for example, in parking lots.

Some cities like Portland, Oregon in the USA have experimented quite extensively with permeable paving. Unfortunately, there is little sign of anything even remotely close being done here.

Perforated Paving Block or Grass Paver

grass paver blocks

Grass Pavers
Image Soure: Wikipedia

These are easily available here but not as commonly used as I wish they were. They are easy to lay and, to my eye, they make a space look much nicer than if were completely covered with a hard surface.

Permeability is excellent but, like porous concrete, it can only be used for low-traffic areas or parking lots.

Tree Guards

tree guard

Tree Guards
Image Soure: Flickr

If all else fails — and even if not, it is wise to have tree guards which allow the soil around the roots to breathe. This is something that is conspicuously lacking in our cities.Instead, we see a low brick wall made as close to the trunk as possible. Apart from being undersized and ugly, these are also tripping hazards for pedestrians.

It would be so simple, instead, to embed a cast iron tree guard that is level with the pavement. If the city authorities feel that the iron will be pilfered, they can do something similar in ferro-crete. It won’t look half as nice but at least it will be effective.

Green Roofs

green roof

Green Roof
Image Source: Wikipedia

While a green roof can’t do very much for the surface runoff and the storm-water systems, it can certainly be help reduce the urban heat island effect.

Planted roofs haven’t caught on too well here as yet. That will not change until waterproofing systems become much more reliable. People who have running battles with monsoon leakage are unlikely to tempt fate.

Conclusion

The situation is far from ideal but it isn’t a lost cause just yet. Given enough awareness and pressure from the general public, things can improve. Organisations like depave, for example, have done this very effectively. They have not only raised awareness in Portland but have even forced the local government to reverse past mistakes.

Maybe it’s time to start something like that in all our cities here as well.

ShKo Bungalow

Many people dream of leaving the city to lead a slower, more meaningful life outside it. Few, however, are able to live that dream. Just a stone’s throw from the [RaBV] bungalow here is a sustainable weekday home of a couple who come into the city on weekends.

Site Conditions

Satellite images of the site showing how the flood zone determined the final house location.

Satellite images of the site showing how the flood zone determined the final house location.

Much of this one-acre site is between 1.5 and 3m above the average water level of River Pej, so during the monsoon, the lower section of the plot is often flooded once or twice for a few hours at a time. The initial plan was to build almost touching the river but that would mean building on stilts. Instead—taking into consideration the high water mark of 2005 which saw the worst flood in living memory—we decided to build on a small rise at the other end of the plot. Thanks to climate change, such freak events as the cloudburst of 26th July 2005 are likely to happen with increasing frequency and we must understand and prepare for them instead of brushing these facts under the carpet.

Because of the sloping land we have a large basement

Because of the sloping land we have a large basement

The little rise is next to the access road so the approach to the car parking area is a little steep but, other than that, there are no disadvantages. There used to be a shed on this mound so there were no trees that needed to be designed around.

As the building is on a slope, the extra height at the bottom has been used to create two basements. One stores gardening and filtration equipment along with the rainwater harvesting tanks while the other has batteries, inverters and other electrical equipment for the photovoltaic solar panels.

The foundations and plinth of the bungalow being made of local black stone.

The foundations and plinth of the bungalow being made of local black stone.

Design Considerations for Sustainability

Climate data for the location which helped make a more responsive, passive solar design.

Climate data for the location which helped make a more responsive, passive solar design.

As with the [RaBV] bungalow, the climatic conditions to be considered were hot days and pleasant nights with a strong monsoon. We needed sufficient shade on the South and West sides and this was taken care of with deep verandahs. Air circulation and cross-ventilation were important to eliminate the build-up of hot air. For the most part, roofs are sloping with only a small fraction of flat terrace where the solar hot-water systems are placed.

ShKo Layout Plan

ShKo Layout Plan

Instead of a typical compact layout, this house was designed as a series of spaces with clear zoning of public and private. When seen from a distance–and a height–it looks like three houses in a cluster rather than just one. Central to all three spaces is the court and the open tank. This is not some amoeboid pool for people to float around with a cold beer but a straight 15m strip for exercise. Oh, and it’s a tank because, well, it’s a tank. Water from here goes to the vegetable garden and to many of the trees on this plot.

The clients, currently in their early 50s, want to spend the bulk of their time here exploring their creative side. Accordingly, one of the major spaces in the house is a workshop to be used for painting, stained-glass making and sliver-smiting. There is also a small study, two bedrooms, a utility room, a living/dining room and a very large kitchen.

Materials & Systems

Exposed brickwork, Mangalore roof tiles and windows made from reclaimed wood.

Exposed brickwork, Mangalore roof tiles and windows made from reclaimed wood.

The foundations were constructed from local basalt and the superstructure from local bricks.We discussed the possibility of using fly-ash bricks but the clients had reservations because of the debate over fly-ash being carcinogenic.

Many internal walls were left un-plastered and the roofs had a steel structure with Mangalore tiles on battens without any under-layer.

One of the old wooden pillars

One of the old wooden pillars on its granite-clad base.

Doors and windows were either beautiful old ones that were salvaged from demolished homes or were made anew from reclaimed old Burma teak. The credit for sourcing them all goes completely to the clients. They also purchased five lovely old wooden pillars during their travels, which were incorporated into the design. Since these were only 2.5m tall, we made a tapered concrete base which was then clad with the same grey granite as was used for the adjoining parapet walls.

Energy

All the lights are low-energy, mostly LEDs, while the fans and refrigerator are inverter-type so their energy consumption is also lower than average. As these fans are a relatively new product, it remains to be seen if they stand the test of time.

Bath and kitchen water is heated using one solar panel on each of the terraces. There are also twelve photovoltaic solar panels on the roof of the workshop which provide enough electricity to run all the lights and fans as well as some of the appliances.

Water

The rainwater harvesting filter

The rainwater harvesting filter

A good amount of the rainwater is harvested. Some of it is collected in tanks for drinking water throughout the year. This is necessary as the river, though perennial, sometimes contains urea washed in from fields upstream; even though the water is clean enough for bathing and washing, it is not advisable to use it for drinking or cooking. The remaining harvested rainwater is used for recharging a bore-well that is an emergency backup water-source. Whatever rainwater is not harvested either seeps into the ground or flows directly into the river.

Embedded dual cisterns flush the low-flow WCs and kitchen waste water is sent directly into a soak-pit from where it percolates into the ground.

And finally, some more images
 View through the brick jali  View of the curved verandah
 View of the Tank  View of the court at night

 

Project Participants

Consultants
Structural & Waterproofing Mr. Ratnakar Chaudhari
Contractors
Overall | Civil, Plumbing, Roofing, Painting Mr. Rajesh Phatak
Electrical Mr. Rafeek Shaikh
Carpentry & Joinery Mr. Ramashankar Mistri
Specialised Agencies
Solar Hot Water Solar World
Solar Photovoltaic | Panels, Batteries, Inverters Sunlit Future
Swimming Tank Filtration Oceanic Enviro Pvt. Ltd.

Indian Green Building Ratings

Magic Tricks & Green Ratings

Green Ratings and the Art of Illusion

I’ve been critical of Indian green building ratings, their basic limitations and the fact that they can and will be manipulated. Of course this is not restricted to India alone… the problem is worldwide.

Now, a study by the New Delhi-based research organisation, Centre for Science and Environment, CSE, shows that a number of buildings that had been awarded platinum status–the highest achievable rating of the Indian Green Building Council or IGBC–were in fact barely worthy of any rating at all based on the amount of energy and water they consumed. Interestingly, the study was based on building performance data on IGBC’s website itself. A defensive IGBC is now nit-picking about CSE’s method of analysis but whichever way you look at it, the fact remains that the ratings methodology looks severely flawed.

How is it possible for the difference between the theoretical consumption–on the basis of which the rating is given–and the actual consumption, to be so vast? To my mind, it strikes at the very root of the problem when the system rewards you for your stated intent (genuine or otherwise) instead of rewarding you for your actions. It is all very well to brag that your building has a fantastic green rating but this has to be borne out by actual performance.

The worrying aspect is, the gulf between ratings and reality has ramifications far beyond mere bragging rights.

Many state governments give tax-breaks and extra floor-space for green buildings so the incentive to obtain a certification can be huge.  It is, unfortunately, all too easy to claim one thing at the time of rating and then shift the goal-posts at a later date.

Now that this latest can of worms has been opened, let us hope for a positive change in the way ratings are given and retained. With so many big names and businesses involved, however, there is always a chance that they will collectively try to sweep it under the carpet; and use the old system of discrediting the whistle-blower.

Acknowledgement: image from Pixbay

ShKo Bungalow at Karjat

The design for the ShKo bungalow at Karjat has finally been completed. It’s taken a lot longer than most because, apart from the complex slope, there was a severe constraint of building within a small portion of the entire one acre plot — the rest is prone to occasional flooding from the adjoining river.

Like other architectural designs, this too makes maximum use of local materials and of passive cooling.  External stone walls are at least 24″ (60cm) thick and provide a formidable barrier to heat-gain even in a place like Karjat.  Deep verandahs on the South and West don’t allow direct egress of strong sunlight from mid-mornings till evening. And high roofs with openings at upper levels allow constant ventilation to take place.

Rainwater harvested from the roof will be collected in the basement that is automatically formed by the sloping land. It will also be used to flood the pool which will not, hopefully, have any chemicals used to disinfect it. The current plan is to do natural filtration but the eventual system will depend on getting a reliable and qualified consultant to carry this out.

View from the gate

Picture 1 of 5

The entrance is set within a recess adjoining the car-port. Deep roof overhangs protect most walls from direct heat-gain. All external walls are at least 24" (60cm) thick and made of local stone to keep the interiors cool even in summer.

SVAGRIHA – a simplified version of the GRIHA Green Rating System

They’re calling it “Small, Versatile, Affordable” GRIHA – a less complicated green rating system for projects less than 2500 sqm. in area.   Quoting from the email they sent me:


ADaRSH (Association for Development & Research of Sustainable Habitats) is pleased to announce the launch of

SVAGRIHA
Small Versatile Affordable Green Rating for Integrated Habitat Assessment

A Rating system for small homes, offices and commercial buildings with built-up area less than 2500sqm

SVAGRIHA is a significantly simplified, faster, easier and more affordable rating system and will eventually function as a design-cum-rating tool. It was required that attention be paid to smaller buildings in India which although have small individual environmental footprints but their cumulative effect is far bigger. SVAGRIHA has been designed as an extension of GRIHA and has been specifically developed for projects with built-up area less than 2500sqm. SVAGRIHA can help in design and evaluation of individual residences, small offices and commercial buildings. The rating comprises of only 14 criteria (instead of 34 of GRIHA) and the interface comprises of simplified calculators. These calculators can be filled using information from construction drawings like areas and quantities of materials. This can be done easily by the architect of the project. Once completed, the tool will tell the consultant the number of points that they are able to achieve in that particular criterion and provide recommendations for any improvements in order to improve the environmental performance of the building.

Process of SVAGRIHA Rating

  • Registration of project with ADaRSH
  • Submission of completed calculators, drawings and other documents as required (quantity estimates) to ADaRSH
  • Assessment/Review as per SVAGRIHA
  • Site Visit and due diligence check post construction (mandatory)
  • Evaluation by GRIHA certified Evaluator
  • Award of Rating.

Note: The site audit to check compliance will be done once the project is complete and all equipment to be verified are installed.

For more information please visit www.grihaindia.org


GRIHA is the national green rating system for India developed by TERI and the Indian Government. I’ve always felt that GRIHA is far more suitable for us than (the more popular & better known) LEED rating system.

SVAGRIHA has just 14 criteria compared to GRIHA’s 34 and can act as a good checklist at the design stage.

SVAGRIHA CriteriaSVAGRIHA point groupsLooking at the point groups, I’m happy to note the weight given to Energy and Water conservation. At the same time, to achieve a rating, the design must achieve minimum standards in all categories. So while they say that 25 our of 50 points will give you a one star rating, adding up all the minimums means you actually need at least 28 points.  And finally, the table below shows the star rating that can be achieved.

SVAGRIHA stars

Appropriate Plantation

There is a raging debate among naturalists about the desirability of cultivating exotic plant species and there are no easy answers. My own view is that we should try our best to avoid introducing any new species into an existing ecosystem but there is no need to get worked into a froth if a species has naturalised over a substantial period of time. Yes, there are places where exotic species have become very invasive at the cost of the local varieties and there may be a case for culling them – but such a discussion is beyond the scope of this article. Instead, we are going to focus on the use of exotic and native species in the context of what is appropriate landscape architecture in a predominantly hot country like India.

Improving Comfort Levels

Trees are often the first line of defence when it comes to passive cooling of a bungalow or other low-rise structure. They provide shade which prevents the build-up of heat not only on the ground but also on the walls of the building. Shade on the ground means the breeze coming in through your window is cooler and shade on the walls means less heat gets transferred indoors. Aside from shading, trees also cool by transpiration to the extent that they can, if properly located, reduce ambient temperatures by as much as 5° compared to the surroundings.

So what kind of trees should we plant, and where?

While the finer details vary across different parts of the country, broadly it is safe to say that the hottest sides are the South and West so, if you can concentrate on protecting these directions with dense evergreens, you’re good to go. On the East, you might want to have high-branching trees that won’t block your early morning sun and on the North – depending on whether you get direct sunlight penetration or not – you could grow colourful, possibly deciduous trees. You have to be careful during plantation that you leave enough distance between the tree and your foundation because many of the large trees have strong spreading roots.

Trees, even in urban areas (albeit to a lesser extent), are part of an ecosystem and need to treated at as such. If they are native, they will invariably be well integrated into that ecosystem along with the local fauna like the birds and butterflies. An introduced plant is unlikely to be so well assimilated and may therefore not contribute in a positive way. There are plants that have been naturalised over a long period of time but I’m referring to those that have been introduced because they are ornamental or because they grow rapidly. Usually the ornamental ones are fragile and drop their branches on your head at the beginning of the monsoon and the fast-growing varieties with their short life-spans often sap the soil so severely that nothing else grows there for years after they’re gone.

Usage of Water

This is a very important factor to take into consideration especially if you’re thinking of sustainable landscaping. Many ornamental trees and bushes are extremely high-maintenance and don’t even get me started on lawns. They may look very pleasing to the eye but, with few exceptions, they guzzle frightening amounts of water and are often heavily sprayed with chemical pesticides — which naturally leech into the groundwater.

Here, a very important argument for using native species is that they will, by default, survive with the naturally available moisture and precipitation. Of course they may need some amount of watering when they are saplings as also during the hot summer months but, in general, their water requirements are a small when compared to exotic ornamentals.

Welcome to bT Square Peg

Based in Bombay (Mumbai) bT Square Peg has been creating sustainable designs in architecture & interiors since 1993.  The primary intention is to seamlessly blend practicality & timeless aesthetics with sustainability — the resources on this planet are not limitless.

design principle:
to seamlessly blend practicality, aesthetics & sustainability

Many designers care more about how the job will look in a magazine article—preferably the cover feature—than it does in reality. This often leads to homes and offices that look very dramatic in photographs but don’t necessarily work in practice. Equally, there are clients who fall into the trap of wanting to showcase the latest rage. Both approaches are wrong in my opinion.

The principle here is to keep in touch with current trends and materials without becoming a slave to transient fashions. Ultimately the objective is to create spaces that are—both physically and aesthetically—appealing to the inhabitants.

Featured Projects


[ShKo] Bungalow

Nasrapur, Karjat [2012-2015]

Courtyard and swimming tank seen through a brick jaliWith rooms arranged around an open court that has a swimming tank, this bungalow is the weekday home of a couple who come into the city mostly on weekends.

Instead of a typical compact layout, this house was designed as a series of spaces with clear public and private zones. When seen from a nearby hill, it looks like a cluster of three houses rather than just a single one.


Satya Health Resort

Vanjarwadi, Karjat [1999-2001]

Entrance aangan to a cottageNestled in a valley between the Matheran and Bhimashankar ranges, on a 50 acre (20 Hectares) piece of land, this is a resort with a difference. It was designed to have the look and feel of a typical Indian village.

The layout reflects the variable contours, with groups of ground-hugging cottages following the gradients. Some units are arranged in a cluster around a central courtyard, while others have individual aangans from which one enters them. Including the unpaved, covered, otlas behind them, each room has almost as much outdoor space as it does within.


Handloom Training Centre

Maheshwar, MP [1994-1996]

Entrance to Kaya KalpBuilt in the historical fort of Maheshwar — old capital of the Holkar kingdom is this training centre for handloom weavers. It was built using only locally available materials and labour, which brought the cost of construction down to a surprising Rs. 1,125/m² (about Rs. 105/square foot). Today that figure sounds almost unreal but, even at that time, it had worked out to approximately one-third of what a similar, concurrent project in the same town had cost.

The walls were made entirely of load-bearing brick with no reinforced concrete whatsoever, and the mortar used was a mixture of lime and cement.


Recycling Water

Apart from saving fresh water there are also some ways of reusing and recycling water so as to reduce our requirement. The technology for this could be hi-tech, like a filtration plant, for example but we will concentrate on basic low-cost solutions here.

Grey Water for Flushing

When we bathe, wash our hands, wash our clothes or get the house swabbed, the discharge that goes into the drain is known as ‘grey’ water (as opposed to ‘black’ water from the toilet). Grey water is sometimes soapy and sometimes contains large amounts of dirt. On occasion, it may have a slight smell but, on the whole, it harbours no harmful pathogens.

This grey water requires only a minimal amount of treatment before it is good enough to use again. You may not want to drink it or even bathe with it but, in fact, you don’t have to come in contact with it at all. You can simply reuse it for flushing.

Apart from reducing your water consumption by almost 50%, if you have a septic tank, re-using grey water has an additional side-benefit that the black water no longer gets diluted by the grey water and, as a result, decomposes more efficiently. Even if you don’t want to build a separate treatment section for grey water, the least you can do is put it into your plants.

Reuse Water for Landscaping

The discharge from your kitchen, bath and washing machine is not harmful to plants so, if you have your own garden, you can always release this water almost directly. In case the food you eat is relatively oily, it might be necessary to install a small grease-trap to take first remove grease from the kitchen waste.

I know someone in the city of Pune who, for years, has released grey water from the kitchen and bathrooms of his bungalow straight into a clump of lush Papaya trees. I asked him pointedly about the chemicals in the soap etc. and he just laughed. He is, by the way, an graduate in agriculture so I guess he knows what he’s laughing about.

The explanation is this: chemicals in detergents and cleaning agents are considered bad because they promote the growth of algae. In fresh water, algae deplete the oxygen which, in turn, kills the fish and other fauna there. But these same chemicals – among them phosphates – also act as growth promoters for trees and are, therefore, excellent for landscaping.

Sewage Treatment

Section to be added…

External Links

To be Added


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Saving Water

There are literally thousands of sites on the internet which will show you ways of saving water. Some boast of having the 100 best tips while others give you five; but almost all of them are useless to us here in India. We don’t clean our cars with a hosepipe (we pay a cleaning ‘boy’ who uses a tiny bucket with a mop) and we don’t water our lawns every week – we don’t usually have lawns to water in the first place. So, on this page, let us not go on about obvious things like “don’t keep the tap running when you brush your teeth”. Let us look at systemic solutions instead, this is an architectural website, after all.

Low-flow Taps and Showers

From an average shower head, the flow averages 8 to 10 litres each minute. So for every 10 minutes of showering, you use between 80 and 100 litres of water. With a bucket, on the other hand, you are likely to average around 15 litres. That is a huge difference and for people who dislike using a bucket, a huge weight on their conscience – or so I would like to believe.

Similarly, though on a smaller scale, when we run a tap, we tend to use more than we really need; but fiddling with a mug while you’re rushing to shave in the morning can be difficult. So we have to look for some other solution to this problem.

If you are willing to, you can simply change the shower-heads and taps to ones that allow a lot less water through. They are classified as ‘low-flow’ and are still quite a rarity in India. They have a design that aerates the water so that although it feels like a good flow, a lot less water is actually consumed. At the same time, the apertures through which the water passes are kept tiny so that the water is forced through and hits you with the same force as a full-flow shower or tap.

Low-flow showers use about 3-5 litres/minute so a 10 minute shower now costs you 35 litres instead of, the average 90 – a saving of 55 litres. Low-flow taps (don’t forget the kitchen sink!) save at least 15 litres per person each day.

If you think that is not much, remember that you save over 25,000 litres every year. Per person! For a family of 4, that’s more than one lakh litres! And if you’re willing to go the bucket and mug route for your bath, you – as an individual – will save almost 30,000 litres per annum.

For the record a lot of people absolutely hate low-flow fittings. In fact there are people who complain that even normal showers flow too slowly for their liking and they actually install on-line pumps to increase the water pressure. If you are one of these people, I know you are going to say that just one person makes no difference. Ummm… Twenty Five Thousand Litres is no difference? Really?

Dual Flushes

Another major way to save water is by changing your flushing system. A normal flush uses 10 litres each time – regardless of whether the bowl contains 100ml of urine or the sum and substance of your latest bout of diarrhoea. On an average day, a person goes for a big job a couple of times and urinates about eight times. With a normal flush, that means you send 100 litres down the drain in 24 hours.

Dual flush systems allow you to choose whether you want a full flush (usually ~5 litres) or just half (~2.5 litres).

Eight urinations + two big jobs:
Grand total for the day : (5×2)+(2.5×8) = 30 litres
That is a saving of a whopping 70 litres which totals 25,550 litres each year. Knock off the 550 litres for all those times when your spouse/parent/teenage offspring complains that “it did not flush properly the first time” and round off the figure to 25k. Not bad, what?

It is a common misconception that such flushes don’t do a good job with the big job. What determines whether the stuff goes away quietly is not so much the amount of water as the design of the toilet bowl itself. Attaching a low-flow cistern to a potty that was designed for twice as much water is not necessarily going to give you good results.

Almost all the major sanitary ware companies make dual flush tanks with matching WCs. Also, recent municipal rules, at least in Bombay (Mumbai), insist that only dual-flush cisterns may be used in all new construction. Some manufacturer links are at the bottom of the page.

Stop that Leak!

Little drops of water make the mighty oceans. If you let all your taps leak all day long for the rest of your life, you would still be unable to fill the Pacific. But you could, very well, fill a large lake. A tap that leaks just a single drop every second, wastes almost 12,000 litres each year. That means throwing away approximately half as much water as you could save by changing your flush tank or by installing low-flow taps and showers.

Do you have a dripping tap? Try the American Water Works Association’s drip calculator to see how much you’re really wasting.

Not getting leaky taps fixed is usually nothing more than laziness on our part because we don’t realise the extent of the problem. That excuse no longer washes, so if you are not handy with a wrench, go call that plumber. And place a bucket under the tap while you wait for his highness.

Choose your Appliances Wisely

Washing machines and dishwashers consume water that would otherwise be used to manually clean your clothes and dishes. While the latter are still relatively uncommon in India, the former are found in most urban homes. So what should you look for when you go to buy one? Aesthetics?

A friend recently wanted a new washing machine that consumed the least possible water. We went to a reputable store that has branches all over town. After looking around, it boiled down to two front-loading machines – let us call them ‘E’ (for a famous European brand) and ‘A’ (an equally famous East Asian company). Front-loaders, by the way, are far more water efficient than top-loaders.

Anyway, we naturally asked the salesperson which model used less water. He hesitated just a fraction and then told us that ‘E’ used 90 litres on a full load while ‘A’ used only 60 litres. This I found surprising because I already had an ‘E’ that used only 49 litres and I mentioned this to the salesman. The latter was adamant and it led to a bit of an argument until we asked him to bring us the technical specifications for both models.

It turned out that ‘E’ does use 49 litres on a full load and ‘A’ uses around 55 litres for the same full load. The point I am trying to make here is that salespeople are usually not trained to answer questions like water consumption and most are not trained to say “I don’t know but let me find out” either. So do not believe what you are told – ask for the printed specifications.

So, Will You?

You can see that the overall saving for a normal user can be anything between 25,000 and 50,000 litres each year. Of course, it will cost you a few thousand rupees and, because water is subsidised in India, you may not recover the financial investment for quite a while. But think of the environmental benefits. You must be concerned; you would not be reading this page otherwise. Fifty Thousand Litres. And that’s just from one person. Go ahead. Make the change. You won’t regret it.

Oh, and if you are seriously thinking of water harvesting then this will actually translate into a lot of money because the cost of storage tanks will immediately drop by almost half.

External Links

Cera Sanitaryware, India
Hindustan Sanitaryware, India
Kohler Sanitaryware, India
Water-saving showerheads. US site
Drip Calculator


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