Why Treat Water in the City at all? Why not live with the Water Purifiers at Home?


I opened the Morning Newspaper and on Page 3 read the news that Neha Malini, a famous Bollywood actor – had publicly announced that she would no longer endorse Zero Water  Purifier . In an exclusive interview Neha said that she felt endorsing water purifiers for  homes is not correct – safe drinking water should be supplied by the municipal corporations in the first place and there should be no need to treat water further at home. She thought that the life cycle impact of a water purifier was worrisome. The newspaper reporter ended the column saying that by turning down the offer from Zero Water Purifiers, Neha sacrificed INR 5 million per year in revenues just based on this principle! And I was impressed.

Wondering what led to this transformation, I called my Professor friend on his mobile phone. He sounded busy but after some pleasantries, when I asked him about Neha  Malini’s stand, he said “Oh, this was expected. It’s all due to the session I did last week  with Bollywood actors – it was a discourse on products they should NOT endorse as brand  ambassadors. And I gave the example of water purifiers and a dose on Life Cycle Assessment. Neha was present during the session. Even Shah Mukh, who was around, is now convinced and will stop campaigning for Safe Water Purifier LLP that he has been supporting for years. See the next Sunday edition of the newspaper for his interview expressing his views”. This was simply stunning.

I met the Professor at our usual café. We ordered coffee with slices of fresh almond cakes. Dipping a slice in my coffee, I asked “Why are you so against home water purifiers Professor?”

Most of the water purifiers in the market today offer 3-stage or 4-stage or even 5-stage water treatment that consist of a filter, activated carbon, membranes for reverse osmosis (RO) and ultraviolet (UV) radiation chamber. The average capacity of the water purifier is 7 to 9 litres and the purifier typically weighs around 10 to 15 Kg. In most purifiers today Acrylonitrile Butadiene Styrene (ABS) is used. Nearly 50% of the weight of the purifier consists of ABS. The RO membranes and activated carbon are required to be replaced once in a year. Assuming you use the water purifier for 4 to 5 years, you will have these replacements done at least 3 times and in this process, waste-activated carbon and exhausted RO membranes get rejected as wastes. At the end of 4 to 5 years, the entire assembly of water purifier needs to be disposed. All these waste streams and components reach the city landfill as these wastes/materials are NOT collected as part of the  Extended Producer Responsibility (EPR) by the manufacturer of the water purifier. There are other issues as well. While the ABS is strong and lightweight material, it is almost impossible to recycle  ABS and further it does not biodegrade. Most purifiers are generally not designed for disassembly, take backs and recycling”

Now look at the energy consumption perspective. Operation of the UV chamber in the water purifier requires electrical consumption of close to 10 W. So assuming half a million water purifiers are operating at homes and offices in Greater Mumbai for 1 hour a day, a  capacity of 15 MW of power generation is needed at the City’s Thermal Power Plant! This would also mean increased GHG emissions.

This life cycle perspective of water purifiers was new to me. The Professor continued his argument

Don’t you think that it’s important that the municipal corporation understands this implication of water purifiers and makes every effort to provide safe drinking water from our taps? In the United States for instance, the Consumer Confidence Rule requires public water suppliers that serve the same people year round (community water systems) to provide consumer confidence reports (CCR) to their customers. The CCR summarizes information regarding sources used (i.e., rivers, lakes, reservoirs, or aquifers) any detected
contaminants, compliance and educational information. The reports are due to the customers by July 1st of each year. CCRs are available on the web for those interested.

If we have such a system mandated in India, I don’t know how many municipal  corporations will have the courage to issue such certificates. In the US and EU, since most of the water supplies are operated by private organizations, CCRs can be imposed. For the water purifier makers, the market lies in the developing world, where there is poor or no assurance on the quality of water supply.”

I knew that the water purifier industry in India was booming. This industry is expected to  grow at the rate of 24% over the next 4 years touching a market of INR 60,000 million! More the cases on the supply of foul water or outbreak of water borne diseases, better is the market for this industry.

The Professor had to rush. While settling the bill he said in a hush hush voice “The other day I was at the city water treatment plant and the supervisor said that the supplies of alum and chlorine to the plant were getting erratic. This was a concern for him. However, in a lighter vein, he said that in any case everyone has a water purifier at home, so a little downgrading of water quality occasionally should not really matter”

A wild thought then came to my mind – can we not do away with the central water treatment systems in Indian cities? If the confidence in the water quality of our supplies is anyway low then all of us could continue to use the Zero and Safe Water purifiers. This will not unnecessarily “duplicate” the efforts and save huge amounts of materials (alum, lime, chlorine) and energy.

I thought that Neha Malini and Shah Mukh should then reconsider and take up once again the endorsements of water purifiers! And the Professor should perhaps conduct another session with Bollywood but now with the new perspective. But what about the life cycle costs of the water purifiers? Unless the purifier makers become more responsible in the design or practice take-back, it may not be a good idea to promote water purifiers at home.

Cover image sourced from www.nbcwashington.com

Interesting read on CCR – http://water.epa.gov/lawsregs/rulesregs/sdwa/ccr/index.cfm

Students – You may like to conduct a Life Cycle Analyses of a Home Water Purifier


  1. There’s also the more fundamental issue – quality assurance.

    City water is supposed to be tested, and to comply with a given standard. That’s why we drink it, knowing that regular quality monitoring is occurring by trained personnel adhering to a set schedule. We need to have confidence in the supplier, or course, that the service delivery is efficient..

    With home water filters, the end product is of unknown quality …….. The operator is untrained, and often does not adhere to the set schedule. So, in what do we have confidence here?

    Fritz Balkau

    1. Dear Fritz

      You hit the nail

      Indeed I would support improving on the reliability of quality water supply. I was sarcastic in recommending water purifiers at home as a “solution”.

      Often water is well treated centrally but gets contaminated when transported through pipes and reservoirs

      A city should be proud to say that ” in this city you don’t need water purifiers at home”

      In the interim, there is no option but to use water purifiers that protect your health. There is no assurance however that water treated through the purifier is of acceptable quality. The issue here is more of maintainence and upkeep -most do not clean filters, replace RO cartridges in time.

      It is important that we realize the life cycle impacts of water purifier as well. Purifier designs should be made for recyclability and purifier makers should practice take backs as EPR


  2. There can be different shades of opinions on centralized water supply vis-a-vis home water purifiers depending on one’s experience with the systems and perceptions. It’s also important to understand that different uses of water require different qualities and hence treating all city water supply to drinking water standard may not be the right option. This is not a topic that could be answered with simplistic solutions. Personally I’m against RO based domestic purifiers as RO is not primarily a disinfection process. There are issues with other disinfectants also. A historical and holistic analysis of water supply is essential to come up with appropriate recommendations. I believe that a decentralized community level water supply will be more effective and sustainable approach.

  3. I think lots of people in the city, don’t take water purifier seriously. But after read your post they will definitely work on that and we can say that, they will use water purifier at home. Thanks for sharing the informative post.

Leave a Reply