Home Water Purification Systems in Mumbai


If you are looking to buy a home or domestic water purifier/filter, read on :


Our Aquaguard was very old and needed replacement. As a matter of details, on most days we used to run the Aquaguard  twice a day – storing treated water in a 10 Liter  stainless-steel tank with a lid. We had an arrangement whereby on switching on the Aquguard unit, the output water directly flowed into SS tank. When the tank became full we had to switch off the unit.  That meant one of us had to stand near the unit, till the tank gets filled. Our source of water supply was BMC supplied water.  Question arose, which purifier should we buy. On & off we had been reading that UV is not a fully satisfactory method of disinfecting water:

  • that it did not really kill the bacteria, it only deactivated bacteria which gets  activated in a few hours in the conducive environment. If this is so, where the treated water is stored for consumption during the day, this method may not be ideal solution for getting completely safe drinking water.
  • That UV does not always penetrate the hard protective shell of CYST (Egg) of diseases causing bacteria & viruses. These become activated once in the stomach, where most conducive environment is available for their growth.
  • that UV penetrated the flowing water stream only to some depth, and part of the water did remain  untreated or unaffected.
  •  To add to this, we were never really satisfied with the level of service for our Aquaguard. Questions to the servicing technicians, like, how are you cleaning the Quartz tube surface, how are you cleaning the scales which get formed over the years, always remained unanswered.  This obviously meant that disinfection treatment our drinking water was suppose to be subjected to was partly in our mind only. Either our strong ‘Indian’ immunity or God was protecting us all these years when we were gleefully drinking our Aquaguard out-put.
  • A question always baffled me; what happens to all the debris of killed bacteria & viruses?  Are they not harmful in any way when we keep drinking millions of them every time we take a glass of water?
  • Add to this, I use to find the AMC charges for our Aquaguard most unreasonable. Consider this: Tata Motors for their Nano car was offering AMC charges which was merely twice that of Aquguard!!!

Our Requirement:

With all these at the back of my mind, we started our search for a water purifier, which will meet the following requirement:

  • It should deliver pure drinking water free of suspended impurities, and 100 % free of bacteria, Cysts, Spores, & Viruses. If the debris can also be removed, better.
  • The process should not introduce any chemicals to the water in the process of purification.
  • The unit needed to have auto start & stop facility to avoid overflow. This was one of the major irritant in our house as often the SS tank will overflow onto Kitchen platform, & in the busy hours of early morning, we will need to clean up the mess.
  • Its recurring cost should be reasonable considering the cost of Parts & labour involved.
  • Initial cost was not so much of consideration. We were prepared to spend, of-course within reasonable limits, whatever it took to get a pure drinking water.

We started with looking on the Net, & lo behold! We come across this site at the first stroke. ‘http://www.indiawaterportal.org/ask/5204’ & what we were vaguely remembering seemed to have basis; that UV may not be killing all Bacteria & Viruses.  Next we came across following news item on the site http://articles.timesofindia.indiatimes.com/2010-09-17/india/28229696_1_purifiers-viruses-filters

This article clearly stated : Most water purifiers don’t remove viruses:

Umesh Isalkar, TNN Sep 17, 2010, 01.08am IST

PUNE: Despite loud promises that these gadgets suck out disease-causing bugs from drinking water, most purifiers sold across India do not completely eliminate water-borne viruses like Hepatitis E, says Pune-based National Institute of Virology.

A study by the government-funded body that conducts research on communicable diseases and viruses evaluated eight domestic water purifier brands. It found only two – one equipped with a hollow fibre membrane and the other with a gravity-fed filter – could completely remove the viruses.

Note: (Size of hepatits A Virus is 28 Nm 0.028 micron, that of Hepatitis B Virus is 40 Nm or 0.04 Micron , Hepatits C virus is 30 to 60 Nm or 0.03 to 0.06 Micron & that of Hepatits E virus is 34 Nm or 0.034 Micron).

These were amongst the first two sites we came across, and only UV based purifier almost became out of race for us.

Thus, purely UV based purifier was ruled out. Next, though we knew that Reverse Osmosis based purifier is really not required when the source of supply is Municipal Water, having ruled out pure UV based purifier, we did not see an alternative at this stage.


So, we tried to study how does RO+UV system from Kent works. We came across following water flow diagram on the website of Kent:

From the page: http://www.kent.co.in/product/waterpurifiers_kentgrand.aspx

On inquiry, we realized that water recovery is around 25 % of total inlet water quantity. This means, to get 20 litres of drinking water, system will use more than 80 litres of water, throwing out 60 litres as rejected water. This looked a criminal waste of water, particularly when RO is not really required as our water is from Municipality

Municipal Water supply has acceptable level of dissolved solids, & these are not only acceptable level, but are most essential for health. As these are essential minerals, above system of UV + RO system tries to add some of it back into purified water.

In addition, above water flow diagram raised several questions as follows:

  1. How a part of water is going through UF while another part is bypassing UF, going to TDS controller directly? Does this mean, that either way it is OK: if water passes thorough UF or does not pass through. How can this be OK? Either all water should pass through or none. So, this looked like some kind of gimmick alright.
  2. How does TDS Controller work? How can it RETAIN after they have been removed?  Inquiry with KENT did not produce any convincing reply. One sales Rep. stated, that it is patented process & they can not reveal how it works. Another stated that a small quantity of source water is added back at TDS controller to create proper balance of essential dissolved solids. Nobody at KENT was willing to come clean if chemicals are not added, then how essential salts & minerals are ‘ retained’ when they have been already removed? And if chemicals are added, which chemicals & how. And, how often this will have to be replenished? Entire series of conflicting answers created more questions than clarity.

At this stage, we decided to give a skip to RO based purifier, as it was really a waste of money & water as far our need was concerned.

So we started the search all over again – which is the best, most sensible (without getting taken in by advertisements & popular beliefs) & operationally economical (without compromising the ultimate goal even wee bit) Water Purifier to purchase?


On further investigation, we came across a model SMART, offered by KENT, which worked on the basis of Ultra Filtration (no sales executive of KENT was very pleased or forthcoming to talk about SMART model as it cost only fraction of UV or UV+RO  model – hardly a welcome buy contributing hardly to the monthly Sales Target!!!, & cost of regular maintenance too is a small fraction of other model.

We discovered that ultra filtration actually employs a membrane based filter with Pore size of 0.01 Micron (Micro meter = 10-6  meter),  & manufacturers made claims that it will filter out all known – even smallest of Bacteria & Viruses. So we embarked on to find out what is the size of Bacteria & Viruses.

Viruses & Bacteria:


Bacteria are among the simplest, smallest, and most abundant organisms on earth. Most bacteria are only 1 micrometer (µm) in diameter, but they can range in size from 0.1 µm to greater than 10 µm.

Bacteria, Fungi and Viruses, Sizes and Significance
(Sizes in Micrometers – MM)

Note: Most are above 0.1M in size. None are below 0.01 in size.

OrganismMicrobial GroupRod Length µmRod or Coccus Diameter µmSourceSignificance
Absidia corymbiferaFungi3.8EnvironmentalZygomycosis
AcetobacterMelanogenusBacteria1.0-2.00.4-0.8Strong beer/vinegar bacterium.
AcinetobacterBacteria1.3EnvironmentalOpportunistic infections
Acremonium spp.Fungi2.5EnvironmentalExtrinsic Allergic Aveons
Actinomyces israeliiBacteria1HumansAntinomycosis
AlcaligenesViscolactisBacteria0.8-2.60.6-1.0Causes ropiness in milk.
AlkaligenesBacteria0.75HumansOpportunistic infections
Alternaria alternataFungi14.4EnvironmentalMycotoxicosis
ArenavirusVirus0.18RodentsHemorrhagic fever
Aspergillis spp.Fungi3.5EnvironmentalAspergillosis, Volatile Organic Compound
Bacillus anthracisBacteria3.0-10.01.0-1.3EnvironmentalCauses anthrax in mammals
BacillusStearothermophilusBacteria2.0-5.00.6-1.0Biological indicator for steam sterilization
Bacillus subtilisBacteria2.0-3.00.7-0.8Biological indicator for ethylene oxide sterilization
Bordetella pertussisBacteria0.25HumansWhooping cough
Botrytis cineraFungi7EnvironmentalExtrinsic Allergic Aveons
CardiobacteriumBacteria0.63HumansOpportunistic infections
ChaetomiumglobosumFungi5.5EnvironmentalChromomycosis, Volatile Organic Compound
Chiamydia psittaciBacteria0.3BirdsPsittacosis
Chlamydia pneumoiaeVirus0.3HumansPneumonia
Cladosporium spp.Fungi9EnvironmentalChromblastomycosis
Clostridium botulinum(B)Bacteria3.0-8.00.5-0.8Produces exotin causes botulism
ClostridiumPerinngensBacteria4.0-8.01.0-1.5Produces toxin causing food poisoning
Clostridium tetaniBacteria4.0-8.00.4-0.6Produces exotoxin causing tetanus
Coccidioides immitisFungi4EnvironmentalCoccidiodomycosis
Coxiella burnetiiBacteria0.5Cattle, sheepQ fever
DiplococcusPneumoniaeBacteria0.5-1.25Causes lobar pneumonia
Emericella nidulansFungi3.3EnvironmentalMycotoxicosis, Volatile Organic Compound
Epicoccum nigrumFungi20EnvironmentalExtrinsic Allergic Aveons
Erwina aroideaeBacteria2.0-3.00.5Causes soft rot in vegetables.
Escherichia ColiBacteria1.0-3.00.5Indicator of fecal contamination in water.
Eurotium spp.Fungi5.8EnvironmentalExtrinsic Allergic Aveons
Exophiala jeanselmeiFungi2EnvironmentalChromomycosis
Francisella tularensisBacteria0.2Wild animalsTularemia
Geomyces pannorumFungi3EnvironmentalExtrinsic Allergic Aveons
HaemophilusinfluenzaeBacteria0.5-2.00.2-0.3Causes influenza and acute respiratory infections
HaemophilusinfluenzaeBacteria0.43HumansMeningitis, pneumonia
HaemophilusparainfluenzaeBacteria1HumansOpportunistic infections
HelminthosporiumFungi12.5EnvironmentalExtrinsic Allergic Aveons
InfluenzaVirus0.1Humans, birdsFlu
Klebsielia pneumoniaeBacteria50.4-0.5EnvironmentalOpportunistic infections, causes pneumonia and other respiratory inflammation
LactobacillusDelbrueckilBacteria2.0-9.00.5-0.8Causes souring of grain-mashes
LegionellapneumophiaBacteria0.6EnvironmentalPontiac fever
MicromonosporafaeniActinomycetes1AgriculturalFarmers lung, Hypersensitivity Pneumonitis
Micropolyspora faeniActinomycetes0.69AgriculturalFarmers lung, Hypersensitivity Pneumonitis
Moraxella catarrhalisBacteria1.3HumansOpportunistic infections
Moraxella lacunataBacteria1HumansOpportunistic infections
MorbillvirusVirus0.12HumansMeasles (rubeola)
Mucor plumbeusFungi7.5EnvironmentalMucormycosis
Mycobacterium aviumBacteria1.2EnvironmentalCavitary pulmonary disorder
MycobacteriumintracellulareBacteria1.2EnvironmentalCavitary pulmonary disorder
MycobacteriumkansasliBacteria0.86UnknownCavitary pulmonary disorder
Mycobacterium TuberculosisBacteria1.0-4.00.2-0.5HumansHard swelling of body tissues. TB
Mycoplasmapneumoniae (PPLO)Bacteria0.3-0.5Smallest known free-living organism
Neisseria meningitidisBacteria0.8HumansMeningitis
Nocardia BrasilensisActinomycetes1.5EnvironmentalPulmonary mycetoma
Paecilomyces variotiiFungi3EnvironmentalMucormycosis
Parvovirus B19Virus0.022HumansFilth disease, anemia
PediococcusacidilactciBacteria0.6-1.0Causes mash spoilage in brewing
PediococcusCerevisiaeBacteria1.0-1.3Causes deterioration in beer
Penicillium spp.Fungi3.3EnvironmentalMycotoxicosis, Volatile Organic Compound
Phialophora spp.Fungi1.5EnvironmentalChromomycosis
Phoma sppFungi3.3EnvironmentalMucormycosis
Pneumocystis cariniiBacteria2EnvironmentalPneumocystosis
Poxvirus – VacciniaVirus0.23AgriculturalCowpox
PseudomonasaeruginosaBacteria0.57EnvironmentalOpportunistic infections
Pseudomonas malleiBacteria0.77EnvironmentalOpportunistic infections
PseudomonaspseudomalleiBacteria0.57EnvironmentalOpportunistic infections
PseudormonasdiminutaBacteria1.0 0.3Test organism for retention 0.2 µm membranes
Rhizopus stoloniferFungi8EnvironmentalZygomycosis
Rhodoturula spp.Fungi14EnvironmentalExtrinsic Allergic Aveons
Salmonella enteritidisBacteria2.0-3.00.6-0.7Causes food poisoning
Salmonella enteritidisBacteria2.0-3.00.6-0.7Causes food poisoning
SalmonellahirschefeldiiBacteria1.0-2.50.3-0.5Causes enteric fever
SalmonellatyphimuriumBacteria1.0-1.5 0.5Causes food poisoning in man
Salmonella typhosaBacteria2.0-3.00.6-0.7Causes typhoid fever
Sarcina maximaBacteria4.0-4.5Isolated from fermenting malt mash
Scopulariopsis spp.Fungi6EnvironmentalOnychomycosis
Serratia marcescensBacteria0.5-1.00.5Test organism for retention of 0.45 µm membranes
Serratia marcescensBacteria1.3EnvironmentalOpportunistic infections
Shigella dysenteriaeBacteria1.0-3.00.4-0.6Causes dysentery in man
Sporothrix schenckiiFungi6.5EnvironmentalSporotrichosis
Stachybotrys spp.Fungi5.7EnvironmentalStachybotryotoxicosis
StaphylococcusAureusBacteria0.8-1.0HumansCauses pus forming infections, opportunistic infections
Streptoccous lactisBacteria0.5-1.0Contaminant in milk
StreptococcuspneumoniaeBacteria0.9HumansPneumonia, otitis media
StreptococcuspyogenesBacteria0.6-1.0HumansCauses pus forming infections, scarlet fever, pharyngitis
ThermoactinomycesvulgarisActinomycetes1AgriculturalFarmers” lung, Hypersensitivity Pneumonitis
ThermomonsporaviridisActinomycetes0.6AgriculturalFarmers” lung, Hypersensitivity Pneumonitis
TogavirusVirus0.063HumansRubella (german measles)
Trichoderma spp.Fungi4.1EnvironmentalMycotoxicosis, Volatile Organic Compound
Ulociadium spp.Fungi15EnvironmentalExtrinsic Allergic Aveons
Wallemia sebiFungi3EnvironmentalExtrinsic Allergic Aveons
Yersinia pestisVirus0.75HumansPheumonic plague


AlkaViva Library http://www.ionizers.org

As can be seen from the above table, smallest of Virus is 0.023 (23 times the size of Ultrafiltration membrane) Micron, while smallest of Bacteria is 0.2 Micron (twice the size of the UF membrane). Review of a few more websites, which could be considered absolutely authentic, like www.cellsalive.com/howbig.htm , Howard Hughes Medical Institute’s website www.hhmi.org/biointeractive/disease/size_analogies.html John Hopkins Institute,  & http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit3/viruses/ssvir.htmlhttp://www.water.ncsu.edu/watershedss/info/bacteria.html, confirmed that smallest of Bacteria is about 0.2 Microns, while that for Virus is 0.023 microns. So it made perfect sense that what is really needed for our home is Ultra Filtration based water purifier.

Fear of Unknown:

(OR fear inspired from self doubts generated because of popular belief or misleading advertisement)

However, doubt persisted. What if we are missing something & we opt out of UV based purifier, & merrily drink contaminated water? So we decided to talk to Bacteriology department of Hafkin Institute. We talked to department of Bacteriology at Hafkin to find out if our thinking had a fundamental flaw. The experts at the department not only  confirmed  all our findings so far, but further advised that some people are indeed allergic to debris of dead Bacteria & Viruses. However, they cautioned us, that the Ultra filtration unit we buy should be based on membrane made out of Polysulfon. They further informed that BARC had developed a technology for Ultra Filtration of Water for domestic & Industrial application, & if we find a unit based on this technology, it will serve our purpose ideally.

This is a method of complete purification whereby not even bacterial debris remain in the water. This process can be compared to the natural purification process occurring in plant tissues whereby plants absorb purified water from dirty subsoil water with the aid of their natural cell membranes.  On comparison, these filters prove to be the best to combat the influx of waterborne, illness causing pathogens.

This settled that nagging self doubt, & we confidently decided to go ahead & buy ploysulfon membrane based ultra filtration unit. Now the question was which company makes this?

So we visited the BARC (Bhabha Atomic Research Center) website to know more about this technology, & to find put which companies are manufacturing unit based on their technology. For benefit of general readers, we give bellow extracts of relevant part of the write-up from the website.

BARC Technology & Salient Features of Unit based on this technology:




Ultrafiltration (UF) refers to the separation of species through membranes on size exclusion principle. It differs from micro filtration with reference to the size of the species being separated. Ultrafiltration membranes are thin polymeric film having pores of the sizes 2 nm to 100nm, operate at relatively low pressure (< 5 bar) and separate the micro species based on size exclusion principle.

BARC has developed and deployed various types of membranes and membrane devices for wide range of water related applications and already transferred the know-how of online domestic water purifier based on ultrafiltration polysulfone membrane to a number of private companies who have successfully commercialised the product in market under different brand names. These domestic water purifiers are of low capacity, zero operating cost gadgets meant to satisfy the need of safe water for small families.

BARC presents the technology for producing Back-washable Spiral Ultrafiltration Membrane Element for water purification (for removal of bacterial & colloidal species) for large capacities, communities and industrial water treatment. At present single unit devices with capacity range from about 0.5 LPM to 4 LPM per unit have been demonstrated, which can be deployed in multiple units for any desired capacity.

Backwashable spiral ultrafiltration (UF) membrane element consists of Polysulphone membrane wound in spiral configuration for compactness. The unit can produce purified water with respect to microorganisms, suspended solids and colloids. The special feature is the backwashability of the UF element to restore its stabilized pure water flux. It removes bacteria and turbidity and produces crystal clear water. These units can be used for domestic as well as industrial purposes.

Salient features of Back-washable spiral UF Units 

  • Crystal clear water free from turbidity, bio-contaminants, colloidal species.
  •  Compact and delivers stable output quality.
  • Ensures continuous operation with less footprint area.
  • Very low operating pressure of about 2-3 Bar, back washable pressure up to 2 Bar.
  • Cross flow mode of operation preferred for higher turbidity feed of >10 NTU.
  • Eco-friendly as no chemicals are used (other than for need based cleaning).
  • Adaptable for high turbidity industrial water (with changes in operating parameters).

We began with making inquiries at KENT to find out what was the material of construction of the Hollow Fibre for their model SMART (Ultrafiltration based water purifier from KENT).Telephonic inquiries with KENT did not produce any satisfactory replies. So we sent them emails to

Mail to their sales office bounced, while mails to service department, inspite of two reminders remained unanswered. However, we carried out our own inquiries to find out performance of KENT’s Hollow Fibre based Ultrafiltration unit.

So we decided to once again concentrate on the unit based on B A R C technology of Spiral configuration of polysulfon membrane. We finally landed on Permionics (www.permionics.com) and sent them the mail to know detail of the technology they are using and technical specifications. The company is based in Vadodara (Gujarat), and with our experience with KENT, we were not very hopeful of receiving prompt reply. To our surprise, they were not only prompt (within less than 18 hours they replied to our mail), but they replied to each of our point very patiently. And, we saw the light at the end of the tunnel. Permionics, not only manufactured purifier based on Polysulfon membrane in spiral configuration with uniform pore size of 0.01 micron, but they seemed to have been manufacturing the same for more than 10 years, and to top it all they seemed to be responsive to customer’s questions. Here, the process of Purification is as follows:

  1. The first stage is the Filter Cartridge which removes suspended matter from feed water
  2. The second stage is the Ultra-filtration membrane which removes all colloidal matter and disease causing micro organisms
  3. The third stage is the Bacteriostatic Silver Impregnated Activated Carbon to prevent microbial growth at point of use, to remove colour & odour and restore the natural taste of water

It is operated through a float control valve, eliminating need to operate it on regular basis. Fresh water is replenished as soon as water level falls bellow certain level. Flushing can be done once in one to two days to ensure long life for the membranes. The company indicates that the life of the membrane will be at-least two to three years. However, inquiries with users in Mumbai show that if flushing is done regularly – preferably daily, then life of membranes can be as long as 5 to 7 years. A new membrane replacement costs Rs. 1800/-

Which means, our last criteria of reasonable maintenance cost (against exorbitant AMC charges for UV/ RO/UV+RO purifier is also satisfied.

Extract from:       http://www.achawater.com/indian-water-Purifiers-review.html

Hazards of Purifier using Chemicals in the process of Purification:

Chemical in water purifiers harmful’

TNN Dec 24, 2010, 04.51am IST

CHENNAI: Most of the storage water purifiers sold in the country use a chemical usually used to sanitise swimming pools, according to consumer activist Bejon Misra. Misra, who is also founder of Healthy You Foundation, was releasing his book titled Safety issues concerning storage water purifiers’ here on Thursday.

Virtually none of the storage water purifiers in the country conform to international standards, he added. “Most of the storage purifiers use trichloroisocyanuric acid, a chemical used to sanitise swimming pools. It poses severe health hazards. Health and safety is compromised for commercial gains. A study by Healthy You Foundation had come out with evidence that leading storage water purifier manufacturers do not declare that they use the chemical to treat water. The government is yet to implement any standard for water purifiers in the country,” he said.

This was not so much of our concern, as we were clear from the start. We will not be buying any purifier which introduces chemicals as a part of the process.

Other companies making Ultrafiltration based water purifier are:

  1. http://www.rupaliaqua.com/smartnova.html (cost Rs. 4000/-. However, they supply separate PET Jar with tap for filtered water storage. Hence, presumption is, it will not have automatic On-Off facility.)
  2. http://www.eurekaforbes.com/water-purifiers/aquaguard-ultra.aspx# (cost Rs. 5990/-)
  3.  http://www.ionindia.com/residentiallink.html#zerp (Zero B Pristine UF)
  4. http://www.kent.co.in/product/pdf/Kent_smart.pdf  (Rs. 5500/-)

Above prices are MRP, without discount etc. Price need to be negotiated with the dealer of individual company. 

Author: Satish Sutaria & Ronak Sutaria

55 Replies to “Home Water Purification Systems in Mumbai”

  1. Thanks for an in-depth research report. The report would have given some lights on the certificates own by purifiers indicated in the report, particularly Permionics, then it would have been more fruitful to the readers.

  2. We can’t thank you enough for the pain you have taken to zero down on the most effective water treatment solutions.

    This indeed comes as a saviour from the onslaught of the RO profiteers. Will ensure that your article is spread out to as many as possible.

  3. Well if I could I could nominate the writers of this article for a Nobel prize!

    Kent’s technology is too mysterious to understand , even their water flow diagram is confusing. Only thing good about them is their advertisement.

    Request all users before buying Kent please ask clear your doubts do not go by looks and advertisements only.

  4. Dear Satish Sutaria & Ronak Sutaria

    Do you know which Hollow Fiber membrane filter Pune based NIV was talking about when they said :

    “A study by the government-funded body that conducts research on communicable diseases and viruses evaluated eight domestic water purifier brands. It found only two – one equipped with a hollow fibre membrane and the other with a gravity-fed filter – could completely remove the viruses.”

    It could really help to know the Brand and Model, so that we can trust the Brand.

    1. Hi Joy,

      Thank you indeed for your earlier comments and appreciation! We greatly value the feedback that we get here.
      Our goal and intent in writing this article was to share our learning and findings, when we ourselves got perplexed with the wide array of “branded” water filter purifiers, and still there was a dearth of factual information.

      Regarding the above question that you have asked to know the “Brand and Model” – we really do not want to recommend any particular brand/model as we feel that each buyer needs to read and understand many of these facts/concepts themselves and then ask the relevant questions to their water purifier salesperson. The goal is really to make an informed decision about the purchase of such an important item, and not get swayed by glossy adverts or big discounts!

      Good Luck with the purchase!


  5. hi.. i want to buy a water purifier but i was having many questions regarding selection of right product. i tried to understand the whole mechanism behind all this so i can select the product which is required for our needs. even after going through many sites my list of que.s was increasing and then finally i found your article and it answered all the que.s of mine. i really appreciate all the efforts you have put in doing all this research and writing it in a very simple, clear and non biased way. it must have taken a lot of time to gather all this info. really it is extremely helpful.

    thank you.

  6. Very detailed description of your quest for water purfiers.Like you i zeroed in on UF membrane filters.An important issue here is the UF membrane filter should be back washable unlike gravity models of kent or Nasaka.Rupali aqua and others are making Barc technology UF filters.If the UF membrane is not washed regularly it breeds more bacteria over time resulting in more microbes than feed water.

    1. Yes, you are right. It needs to be back washable. That is the beauty of Permionics model. It has facility for you to carry it our once a day by simply turning on one Tap provided for the same. You keep it on for say five Mins a day & job is done.

  7. very helpfull guided research, you went too deep for right choice which will help people like us to choose and decide. thanks

  8. Indeed a VERY VERY informative article over the issue and definitely to the point

    What are your views on Dolphin Deluxe UF?
    i mean specifically does it back wash ? also it contains Alumina is it really help full ?

  9. Dear Sirs,
    Firstly thank you for this great article. However, i am still stressed re a water purifier. Which one to buy. We live in Andheri west, Mumbai and get water from Bmc.
    However the building tank is not always cleaned on time etc… so i would request you to suggest a brand which i may purchase.
    Would request you to let me know. I cant really figure it out for myself and nor can i trust these sales guys to be honest.
    Many thanks.
    Kind Regards

  10. thanks for a well-researched article. It is very useful as it eventually boils down all the research to a specific set of recommendations.

  11. Informative, brilliantly researched and echoes my views on the big brands with poor quality service despite elaborate contracts. Thank you so much

  12. That was beautifully explained basic concept. Remarkable work without bias. (really imp). Thank you for the efforts and information.

    1. Dear Sir,
      I totaly agree with you. Many of us buys product from TV advertisemsnts, If yo see Fair and lovely is selling cream from sa many years how many black people it can convert to white? It is not possible still people buy like that looking at TV advertisement many people ask for RO water purifier for Municipal water means treated water?
      You have covered all the points thanks for your article.


  13. you have done a very good job for us. after reading your article i have finally gone for pureflow uf for my daily need of purified water. though in surat smc is said to have best water treatment plant and quality of their water is too good i decided to go with pureflow uf. will share my experience later on.
    thanks to you once again.

  14. Thanks Satish and Ronak, for your article with in depth research. We are facing exactly the same problem that you have mentioned with eureka forbes and were wondering which one to opt for replacement. Now we know which type of water filter we have to go for, but have to short list the brand.

  15. Thanks for this – This popped up while i am doing my own research on buying a UF + UV water filter.

    I came across this:
    1) Hallow Fiber Membrane
    2) Carbonit IFP ultra Filter

    How to find out which one is better and has a backwash.


  16. Hi

    Thank You very much for doing detail analysis and research and then putting your findings online for the others benefit. once again tank you for all your good work

  17. Hi, I stay in Mumbai and want to replace my EF Aquaguard as it is not working to our satisfaction.

    UF: to be used if the water is supplied from BMC as the TDS is less than 100
    NF: to be used if the water is supplied from BMC and there are tanker water for 10 days a month.
    RO: to be used where there is borewell water.

    Where i stay they have BMC water supply on all days so he said that without even thinking twice, i should buy on UF technology & not any other. Their pureflo UF is for 7750, expensive than other UF products in the market but he explained that the product is very superior as other use chinese membrane which wear in 2 years and their product will work for 8-10 years if maintained. The guy sounded pretty genuine. Hope this helps. And btw Sutarias you guys rock, great research.

    All the best

  18. Hello,

    A very well researched article I must say. Very helpful. However while going through

    some more random info on google, it mentioned the ph factor of 7 is needed in water

    which is very necessary to avoid drinking acidic water. And which is lost in these

    filtration processes. I am using eureka forbes eboiling Nova, a very old modal since

    almost 10 years. It only needs a change of carbon and filter candels for approx. Rs. 800 every 6 to 12 months. We get municipal water but at the times of short supply our society mixes borewell water in the society tank. Also I have doubts about cleanliness of society tank where we get our water from. The service guy from Eureka Forbes DSA checked the TDS of water and it was 150 which he said is OK and we should continue with this modal. He did not had any other checking appratus for water quality. He did not seem very educated either.

    I have observed deteriorating digestion and frequent illness in the family and I doubt its because of water we are drinking.

    I don’t mind spending even a good amount for a sure shot drinking water cos Family

    health Problem looks like so big right now. Also as your article was written in 2012,

    I think some latest modals using latest upgraded technology might have come to the

    market. I could not compare and select any one out of these 500 diff modals with 5000 diff features being technically challenged at this aspect.

    I really really request if you could please suggest some latest modals with latest

    technologeis so I can buy that. It would be highly appreciated.


  19. Hello sir,

    Kudos to your article. 100 marks for well done and well presented research.

    It Helped me identify the technology that i should choose for my home filter ( mumbai resident – bmc water supply) … No confusion there.

    Now my dilemma is – i hv chosen two companies – permionics and blue dolphin – as my final candidates and i need to decide which one to choose.

    I compared the two models and found out that one uses spiral wound membrane and another uses hollow fibre membrane – dont know which one is better.
    Lots of reading up of internet articles also didnt tell me very clearly which membrane is better for home purfiers…. Both are popular choices…

    Then spoke to permionics represntative who told me that their pureflo UF model uses 0.001 micron thckness memb whereas blue dolphin uses 0.01 micron…

    As far as i know 0.01 micron is sufficient to remove bact and viruses – so their a merit in using a 0.001 micron … I dont know…

    Next difference – permionics model has a backwash facility ( but it does not remove 100% debris – only abt 70%. – permionics sales mgr said this) – whereas blue dolphin has manual cleaning….

    so is backwash really a diffrentiating point between permionics and blue dolphin cos both are not 100% effective..

    According to me memb technology is a simple technology – only membrane quality and ability of the unit to keep the membrane clean will determine which pdt is better …. And till now i havent been able to make up my mind about either of them.

    Look forward to your inputs – to help me decide – as i have to make a decision in the next few days…

    Many thanks for your help


    Neeta ashwin

  20. A very well researched article. The authors have put in a lot of work writing the article to help water filter buyers. We read from other sources that too clean is not desirable, as 200 varieties of bacteria are our tenants in our body in every pore of our skin and also inside us from mouth to anus. We cannot lead a healthy life without our bacterial tenants. In such scenario, there seems to be a danger of too pure being harmful for us. What is the limit? For the information on our bacterial tenants one can access ‘you tube’ and hear lectures by Dr. BM Hegde on this subject.
    There seems to be an upper and lower limit for cleanliness for humans. And that is the dilemma.

  21. Dear Satish & Raunak,
    Your article is a kind of ready reckoner and is serving as a reference guide…..Great Job.
    I am a resident of muzaffarpur in Bihar and need your advise on the kind of water purification system i should get installed at my home.We have our own borewell at a depth of 300fts and the water from the same is being used via overhead tanks.We are presently using a storage water filter of USHA BRITA but having great trouble procuring its cartridges.The drinking water we take directly from the borewell and store it but now we want an online system.The TDS is 555 ppm of the water collected directly from the borewell.Their is lot of scaling on the utensils and plumbings at our home and the guy who measured the TDS said that the iron and calcium content is high
    Kindly suggest me the best technology and the brand of water filter i may opt for.Your quick response will be highly appreciated as i want to change the filtration system instead of changing the cartridge of my old water filter.
    with warm regards and thanks in advance.
    s.faizi akhtar

  22. About the Kent water flow diagram explanation, I believe it works as,
    1. Water going through UF, getting mixed with water output from RO membrane, but with regulation using TDS controller, which is adjustable.
    2. As per your article UF also removes bacteria and virus, but it does reduce TDS, so this high TDS water is mixed with low TDS water from RO, in desired proportion to get desired TDS. If incoming water is already a low TDS (<100 mg/l), then RO is not needed.
    3. This side way water flow from RO membrane also increases its life, due to flushing of water impurities.

  23. Hi! This report / article was really helpful. I have planned to share the link over Facebook so more people benefit from it. Also, it saved me money as I was about to invest in an RO Water purifier too, in spite of having access to PMC water.

  24. dear both ,
    this is a great research you have done.Today being sunday I was about to finalise with eureka forbes but luckily you have saved me and I read this article and now I will properly choose a right brand having right fit of technology as per my need. I live in kandivali east 90 feet road & we get regular 24 hrs BMC water. It would be great if you can suggest a right brand for my needs. Kindly email me separately on email id ( deeammehta@gmail.com) in case you do not wish to publish it on common forum as if it seems you do not wish to be in favour of a particular brand. This is good & ethical stand. We all appreciate the same but kindly suggest to me as I am really in emmergency as my wife has been sick from last 4 months off & on. I found that water may be one of the reason so just want to do it as soon as possible.

    please help me sir. My cell no is 88795 98668 in case you wish to SMS the final brands.

    Thank you for your time & support.
    Dayal Mehta

  25. Dear Sir,

    I have never seen such an exhaustive research on water till date. I also have no words to express my gratitude to you for doing this study. It would have been a great help if you could conclude the research and study by finalizing the brand/model of ultra filters and the cost involved. I would also like to go for one please. Kindly request you to please mail me details at nitin16rao@yahoo.com..

    best regards….. Nitin Rao Chandavar

  26. Dear
    I am staying in pune at Balewadi ,currently i am having 300 to 350 TDS boring water given by builder .
    As you mention (BARC technology) use only for (BMC or PMC goverment water whose TDS is low like between 50 to 100 TDS ).
    My question:
    1)Currently i am getting boring water of tds 300 to 350 for that which purifier need to buy and later some year after i will get (PMC -corporation water) that time tds is 50 to 100 ) for that scenario which i need to buy ,please suggest .
    Please suggest water purifier for high TDS level betwwen 300 to 350.

  27. Hello guys what a nice blog that has information about water purifier as these come with RO and UV filtration process to protect from germs, bacteria and viruses. I also use purifier. Thanks for the information. Keep it up.

  28. Hats off to you both guys!!
    This is tthhee best report on water purifers anybody has written.
    An answer to a water purifier purchase advice seeker (a Mumbaian or other India’s metropolitan city residing person with decent Municipal body for water supply)

  29. Thanks a lot of the beautiful and well articulated essay. It is indeed helpful and can help unfold our eyes from the blind strips of the advertisements that we follow over the television.

  30. This is a wonderful article. I am tired of aquaguard and their service people who badger us to take AMC. I have been thinking of boiling and filtering with old steel filters with candles. They were more reliable. I don’t understand why we changed it when it worked so perfectly. Reading your article has given me the realisation that all those tall claims by the companies are mere marketing gimmicks. Thank you.

  31. Brilliantly researched article.This blows the lid of the propaganda of most of the big water filter brands in India!

  32. superb article, you cleared all my doubts;now i am very much sure, what we have to look while purchasing good water purifier. Sir, UF AND NF are different kya? Kindly clarify.

  33. The moment I started reading this post, I felt we were soulmates. I am in exactly the same situation, needing to change my Aquaguard and bombarded by all kinds of misinformation from ads, internet, and so-called technology & model comparisons which should be tossed in the trash. Your thorough research has answered every question a buyer could have. A very noble undertaking and superb result, guys. Many, many thanks!
    What’s your opinion on Whirlpool Destroyer?

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