Thursday, July 25, 2019

Some Thoughts on Hydrogen Water

Hi Chen Ko,

I am Kenny, similarly i have great interest in drinking water. I started this journey i was put incharge of fresh water system during my national service with the navy. There was a time i am the project manager for <> from water technology. I have not much interest of PH and alkaline, and i agreed on your point on PH and alkaline. But i wish to hear your view on Hydrogen Rich Water and negative ORP for water from natural way, not the ionized way. Thank you


Hi Kenny,

My take on hydrogen water is still the same as my last post on the subject.

In a nutshell, there is insufficient evidence to prove beyond doubt the various health benefits of drinking hydrogen water. Google it up and you can find lots of such claims.

A few facts about hydrogen

  1. Hydrogen gas (H2) does not dissolve well in water, even less so than oxygen gas. You may be able to hit a respectable solubility of 0.3ppm (mg/L) so even if you drink exclusively hydrogen water at 3L/day, you are only taking in 1mg of hydrogen per day. Is that enough for providing the claimed health benefits? I don't know...
  2. Hydrogen is the smallest known molecule. That makes it very mobile and penetrating. It can pass through physical and biological barriers e.g. cell membranes, even through metals. Sure, it can reach into the depths of your body and perhaps confer some of those mentioned health benefits. On the other hand, it can just as easily escape from your body without staying inside long enough to work its magic.
  3. Earlier, I mentioned about hydrogen penetrating metals e.g. steel. Usually, this is bad news as it creates "trails" through the metal, thus weakening it and possibly enhancing other forms of corrosion within the metal. What does it do as it goes through the human body so easily? Can there be adverse effects in a biological system? I am not sure...

I am not exactly sure what you meant by hydrogen water produced by the "natural" way as opposed to the ionised way so I can't say for sure their differences. However, if it is still the same hydrogen gas dissolved in water, then the above facts still hold true.

Figure: Canned hydrogen water selling for a few dollars per can. For illustration purposes only, definitely not an endorsement.

Thursday, July 18, 2019

Revisiting: Do we really need water filters?

The original post with the same title "Do we really need water filters?" came out almost 9 years ago and it is still one of the most well read posts. Along the way, I have written many other posts to further explain this fascinating topic.

Recently, a well known media company interviewed me on the various aspects of drinking water in Singapore - bottled water, water filtration, alkaline water, tap water. Eventually, my interview was not published but I will not go into the reasons here.

However, I found one particular question to be highly relevant for a revisit: are there any benefits to installing filters in homes?

Seriously now CK, do SG homes actually need water filters?

Long time readers of my blog probably know that I am not an advocate of water filters in the SG home. Our tap water is good enough to drink straight so why do we need to fork out our hard earned Yusof Ishaks for an "unnecessary" filter and its never ending replacements?

With the benefit of age (Uh, I mean experience) and its companion known as hindsight, there can indeed be benefits to using a water filter in the SG home.

Peace of mind

I am not kidding! Psychological health is every bit as important as physical health. Healthy mind leads to healthy body, right? If you are totally convinced that you need that ABC water filter to allow you to drinking healthily, please go ahead to get it (within your means of course). For that matter, if you absolutely need that alkaline (or hydrogen or ionised etc.) water to function at peak efficiency, please go right ahead. You know you body best and if you believe it benefits you, I will not argue with that.

Reducing intake of controversial pollutants

Let's face it - even WHO drinking water guidelines are not omnipotent. They cannot be 100% reliable in their recommendations. Nevertheless, they are still VERY useful and possibly the best currently available guidelines for drinking water.

Over the years, various chemical species have received much attention in parts of the world. One is chlorine which is the most common disinfectant. Under the right conditions, it can give rise of various other chemical species in water. They are known collectively as disinfection by-products (DBPs) and have various levels of negative health effects.

The other water treatment additive is fluoride which supposedly fights tooth decay. It has its fair share of opponents citing concerns about fluorosis - a condition caused by an overdose of fluoride.

And if you want to reduce the levels of such controversial pollutants below the levels currently found in tap water, you have to install your own water treatment unit. Just make sure that it can indeed reduce these pollutants to a level you feel safe.

Reduction of actual pollutants

In my opinion, the chances of this happening is rarer. Reasons are usually accidents, human error or else something has gone wrong. Who is to say it is impossible that your water supply piping may just happen to be cracked and sewage has somehow entered it? Then you are looking a possible dosage of human pathogens in your water. A water filter that can eliminate pathogens will come in handy.

I still remember the time when the body of a maid was found in the water tank of a HDB block. This kind of situation basically contaminates the water supply of the entire block. And if you are using an effective water filter, more power to you.

Better taste

I have met individuals sensitive to the taste of chlorine in their water. And if you are one of them, sure, get a filter to remove chlorine. The other group of people will be coffee/tea aficionados. They aim to brew the best cup of coffee/tea at home and will spend resources to achieve this aim. A water filter to remove chlorine and possibly metals become a necessity.

Actual health issues

Though rare, it is possible to have chlorine allergy or allergy to any of the other impurities in water. In such cases, removing chlorine (or other allergen) from drinking water and other sources of skin contact (think bathing, washing) is necessary. I am no doctor but I imagine there are patients who need to be cautious about the kind of dietary intake through drinking so they need water to be purer than a normal tap can supply.

10 Tips To Get Those Taste Buds Working As They Should ...
Figure: My kind of taste enhancer for drinking water if I ever find plain old aqua to be bland

Is RO (reverse osmosis) water drinkable? Busting some of its myths and reiterating some of its truths

RO (reverse osmosis) water used to be all the rage 10-20 years back. Heck, you almost found RO in every water treatment device in the domestic market! You would surely be forgiven for believing that RO WAS the only water treatment available for the consumer.

Well, the rage has quieted down somewhat now. We see a lot of other water treatment methods nowadays - UV, microfiltration, ultrafiltration, activated carbon and specialty (usually means proprietary with little information given to the consumer) filter medium.

Why the declining interest in RO? I suspect that both suppliers and consumers are waking up to the drawbacks of RO, both real and perceived.

(In this post, I am talking about freshwater RO in the home. Seawater desalination as a water utility also makes use of RO but there are many important differences. See my previous post for more information.)

Myth 1: RO Water is too pure and doesn't provide minerals for the body

One thing I have to admit is RO is so darned good at removing "impurities" from water. Impurities include beneficial minerals needed by the human body and/or for aesthetic considerations. Some of my personal sources swore that mineral water tastes much better than bland old distilled water. (Like RO, distillation can remove lots of impurities too.)

Without going into math, we are better off getting our mineral intake from our food rather than water. Look at it this way, the concentration of minerals in water (even mineral water) is miniscule. You have to drink a hundred litres or more per day to get your recommended dose. Furthermore, if you talk to a dietician, she will convince you that the chemical nature of minerals is food makes them easier for absorption into our bodies.

Myth 2: RO Water leaches minerals from the body

Continuing on the logic that RO water is so pure, some pointed out that its drinkers will experience the double whammy of not getting their dose of useful minerals, as well as having the existing minerals in their bodies leached out by the RO water passing through their digestive tract.

One, the biochemical condition in our bodies is constantly maintained (aka homeostasis) or our bodies will simply not work. The mineral content in our bodily fluids is especially stabilised by our kidneys which control the amount of minerals wasted into our urine. Sorry, minerals do not simply leach into our digestive tract.

Two, sailors have been drinking RO water on a long term basis on board ships and submarines. We have yet to see any evidence of adverse effects.

Fact 1: RO "wastes" part of your water input

To me, this is significant no-no for water treatment. For every litre you feed into RO, you only get half (can be more or less depending on various factors) of it as treated output (aka permeate). The other half is known as retentate or concentrate and disposed.

Sure, the concentrate from a domestic RO unit probably is only 30% or more concentrated compared to the feed but no one in his right mind will want to drink it as it totally defeats the purpose of RO in the first place. And sure, you can use this concentrate for other purposes e.g. irrigation, washing. But to me, that does not change the fact that you are only getting half the water for drinking.

Fact 2: RO is an overkill

For those who have not read my practical guide on 3 Critical Questions on Choosing Your Water Filter, I suggest you visit the link, download it (it's free!) and sit down to read it.........

Finish reading? If you haven't, here's the short version. Basically, before settling down on a water filter/purifier/treatment unit, you have to do some homework, specifically, know what impurities are of concern to you, what levels are they at in your raw water and whether your chosen treatment unit can remove them down to "safe" levels.

RO is an expensive (you need to pay for the high energy usage to generate the high pressure inside) and wasteful (see fact 1 above) water treatment method unless you have no other choice to remove your impurities of concern. Sure, the water output is pretty pure but most of us do not need that kind of purity unless you are manufacturing pharmaceuticals or electronic wafers in your home. Heck, coffee and tea should not use this level of purity as various sources have claimed that a higher mineral content is needed to bring out the optimum taste in them.

Figure: Typical RO system incorporating other water treatment methods. RO is never stand-alone. The entire system tends to be rather bulky so you have better allocate enough real estate to keep it.

Friday, March 08, 2019

A too good to be true water filter?

Hi Chen Ko

Thanks for sharing your knowledge on Singapore's water quality. Your blog has been extremely helpful in my search for a new water filter for my family.

Yesterday, I chanced upon this review:

Cleanwater4less is only about 50usd and has 10000 gallons capacity. This means it will last 10 years for my family if we use 10 litres each day! Does it sound too good to be true? 

The reviews in amazon are generally good except for a few reviews saying that carbon particles came out from the spout. Perhaps they didn't follow the instructions to let the water run through for 10min before using the filter. 

I was thinking of getting a Royal Berkey but now I have second thoughts. Hope you can help me take a look at this product and advise me if it can really filter water properly. 

I just need a basic filter that doesn't need frequent replacement and can help me cut down on boiling water at home. 

Looking forward to your advice. 

Thanks and best regards 


Hi YC,

Glad that you find my blog useful in your search for a water purifier/filter.

I have to reiterate that my stand is water filtration or treatment is not required for Singapore tap water unless you have certain medical issues that require drinking filtered water. Nevertheless, I understand that some readers have certain health concerns about drinking tap water e.g. chlorine, fluoride and I respect your concerns. These concerns tend to be controversial and by no means conclusive one way or another. Therefore, I see no issue in getting a water filter just to achieve peace of mind.

Back to your question. Doulton and Big Berkey to me are 2 trusted brands and products in the water filtration world. And for good reasons...
  1. They have a long record of good reviews. 
  2. They are certified by ANSI/NSF standards (NSF/ANSI Standards part 1, part 2). 
  3. They also show their filter performance data to the public. (In my opinion, their data are still not good enough but much better than many other suppliers who reveal little or nothing.)
I am afraid the product you recommend can hardly match the above factors. I find its reviews too generic in nature with barely any quantitative comment about the performance of the water filter.

There is a good reason why domestic water filters WITH ACTIVATED CARBON (not the pure ceramic ones) are often rated for only hundreds to perhaps a thousand gallons of water before a replacement is needed. That is because conventional manufacture for AC can only achieve that much filtration before it becomes saturated and useless. If you see an AC filter that can handle 10000 gal and costs less than $100, it is a big red flag.

The final decision of course lies with you. Still, I hope you find the above discussion useful.

Figure: Doulton filter performance data

Tuesday, February 26, 2019

Can you extend the recommended operational duration of a water filter? Part 2

This post is a continuation of a previous one.

Here is an extract of the original questions of which I have yet to answer.

  1. Based on the (considerably low) fluoridation levels in Singapore's water, is it possible to actually calculate a suitable replacement period for my Fluoride pre-filter cartridge? This is assuming that I may replace it at longer intervals compared to my ceramic candle, instead of replacing both at the same time. I'm presuming here that the ceramic candle will need to be replaced earlier - but do enlighten me if this is likely to be so.
  2. Is it a good idea to store up replacement cartridges (be it Fluoride pre-filter or ceramic) for a year or two before use? Not sure if the material and elements will degenerate/degrade slowly.

Dangers of delayed filter replacement

  1. I wouldn't be too worried about the silver leaching out. Even if it does, its concentration is likely to be very low in your drinking water.
  2. I would be more concerned about the filter not doing its job properly and allowing the contaminants that you want to remove to straight through into your drinking water. In this case, you may as well not install a water filter.

    Worst case. If your filter is mechanically broken after too long a usage e.g. cracked, the raw water will go straight through with no filtration regardless of whether your filter media are still effective.
  3. Another possibility. Though filters impregnated with silver are supposed to resist bacterial growth, this is never a guarantee. If your filter element has accumulated so much debris after years (gasp!) of continuous usage without cleaning, expect germs to grow on the debris. Just hope that they don't go into your filtered water and if they do, they are harmless to health.

Calculation of a replacement period

  1. If you want an accurate calculation, you will need detailed experimental data for the filter e.g. equilibrium curves, breakthrough curves AND data of your own water usage and tap water quality. Since filter suppliers and PUB never give out such data and neither of us has the resources to conduct such tests of our own, accurate calculation is out.
  2. A rough calculation is still possible. BUT remember the assumptions filter manufacturers make in my previous post? You at least need those, especially the water quality the filter is designed for.

    If you managed to get those information, do let me know and I can do a calculation for you. A caveat though, a rough calculation like this works on certain assumptions (yes, this word again) so treat it as an estimate and don't bet your life on it.

Storage of replacement filter elements

  1. Unused filter elements from reputable suppliers should have no problems being kept in storage for a year or 2.
  2. Just ensure that the storage space is clean, cool and dry to minimise chemical/mechanical degradation and biological growth.

Figure: Big Berkey replacement filter elements

Tuesday, February 19, 2019

Can you extend the recommended operational duration of a water filter? Part 1

Dear Chen Ko

I hope this email finds you well!

Thank you for your insights which helped me greatly in choosing a water filter previously. Doulton has served me well. 

I write again for your advice on when to replace filters - the most troublesome part as it can be a bit of an art and science, especially where there is no replacement indicator on the filter.

  1. The recommended period for replacement for my Fluoride pre-filter cartridge and ceramic candle was
    9  to 12 months. However, because of [a] what I view as low usage (about 6 litres a day), and [b] also the fact that the ceramic candle can be periodically cleaned (not that it is terribly yellow either), I had not followed this recommendation. 
  2. Based on the (considerably low) fluoridation levels in Singapore's water, is it possible to actually calculate a suitable replacement period for my Fluoride pre-filter cartridge? This is assuming that I may replace it at longer intervals compared to my ceramic candle, instead of replacing both at the same time. I'm presuming here that the ceramic candle will need to be replaced earlier - but do enlighten me if this is likely to be so.
  3. Is it a good idea to store up replacement cartridges (be it Fluoride pre-filter or ceramic) for a year or two before use? Not sure if the material and elements will degenerate/degrade slowly.

I look forward to your thoughts on this topic. Oh yes - and a very Happy Lunar New Year to you!



Dear Paloma,

A very Happy Lunar New Year to you too! And good to hear that my recommendation has been useful to you. (For new readers to my blog, I do not derive any benefits from my recommendations unless explicitly stated otherwise.)

You have touched on a very relevant topic on water filters and yet there is so little useful information out there for the consumer. This is not without reason though.

Manufacturers of water filters make recommendations (say 3, 6, 9 or 12 months) of when you should change your water filter. 
  1. Such recommendations are obviously based on certain assumptions e.g. number of people in a household, amount of drinking water consumed per person per day, tap water quality which may or may not apply to the consumer. Unfortunately, these assumptions are usually not communicated to the consumer.
  2. There are filters out there with their operational lives given by the total volume of water filtered (say 1000 to 100000 gallons). Though still based on certain assumptions e.g. water quality, this is a lot more accurate than a time based measure. The obvious downside is the consumer will find measuring volume a lot more difficult (or expensive) than just keying a date in the calendar for replacement.
  3. The operational duration is typically a conservative value to safeguard the claims made by the manufacturer who is confident that the filter can work effectively within given period.
  4. Remember how printer suppliers earn their profits from you buying their printer cartridges? Same here. You are expected to change your filters regularly to provide  consistent profits to the water filter suppliers.

Besides time, are there other ways to know if your water filter is up for replacement?

  1. Some purely ceramic filter elements (no activated carbon (AC) or other fanciful filtration media incorporated within) come with a ceramic gauge. The idea is a ceramic element can be scoured periodically to remove the residue on its surface. Scouring also removes some of the ceramic, gradually thinning the ceramic. The gauge serves to measure the thickness of the ceramic so once it goes beyond a certain limit, the element is no longer effective.

    Unfortunately, if your ceramic element does not come with a gauge, you are out of luck as there is no way to guess/calculate/estimate the thinness of the element before it is due for replacement.

    Or if your ceramic has AC or other media impregnated within, the AC or media will determine the life of the entire element as their effectiveness tend to run out MUCH faster than the ceramic itself. Incidentally, you did not mention which Doulton element you are using.
  2. Total volume
    Already mentioned above but I just want to add that if you are really keen to keep track of the total volume of water filtered, you can install a flowmeter to automatically monitor this for you. Not cheap and not practical for a gravity filter, it is nevertheless an accurate way to tell you when to change filter.

    A cheap version of the above test is to work out your daily volumetric usage. Divide the capacity of the filter by your daily usage and you get your operational duration. This is provided the filter manufacturer has specified the capacity of the filter in total volume.
  3. Blue dye test
    Certain filters incorporating AC allow you to test their effectiveness by running a blue dye solution (prepared by e.g. adding 2 drops of blue food dye into a cup of water) through your filter. If the filtered water has no visible blue colour, the AC is still working well. Otherwise, it is time to change filter. (Apparently, blue is commonly recommended as other coloured dyes do not work so well.)
  4. Colour, odour, pressure drop
    Depending on a degradation in the colour and odour of your filtered water is somewhat like waiting to do something only when the problem arises. A reactive kind of attitude at best and dangerous at worst when contaminants from the raw water are already going into your drinking water.

    Another reactive solution is to wait for the filter to show an apparent drop in pressure i.e. your filtrate is not coming out as fast as before. Usually, this means the filter is clogged up with residue. Contaminants may or may not be going through the filter. Time to change filter or in the case of a ceramic element, time to scour its surface.
  5. My solutionAs I don't use my Doulton filter regularly so I estimated the volume filtered in each trip and keep a record with the filter. Once it has reached the rated capacity (say 2000 litres), I changed it.Still, if the filter looks dirty or the flow is not smooth, I scour the filter surface. I keep a record of scouring too together with the usage. I believe Doulton specified a maximum number of scouring at 100 but treat this number with a pinch of salt as ultimately, it depends on how rough or gentle your scouring session is.

I believe this post has gone on longer than I wished. Thanks for your thought provoking questions. Let me answer the rest of your questions in another post.

Good luck!

Figure: A flowmeter that can total the volume of water passing through. Expensive but very useful to tally the amount of water going through your filter

Sunday, February 17, 2019

Water quality standards for bottled water?

Dear Chen Ko,

I am Bob searching for information about safe drinking water qualities from internet.

The web  bring me to your blog and found that you are knowledgeable about drinking water.

I am writing to ask you about safe drinking water qualities from bottled water dispenser.

Please look at the 2 photos carefully. This water dispenser is located in our working office.

Can you please advise what are the safe allowable TDS, pH values and other controlled parameters

for this bottled water dispenser as regulated locally or by international association?

Thank you for your helps.

Best regards,

Hi Bob,

I must confess that bottled water is not my favourite type of drinking water. Overall expensive and water of questionable quality, this is not my first choice for the office. If you absolutely need a hot/cold water dispenser, one incorporating reliable water filtration of tap water will be more economical. Singapore tap water is already quite good to start. Add in a good water filtration system and it should satisfy most people who have concerns about drinking tap water. And you do not need to call the vendor regular to resupply the bottles. Just change the water filters as instructed and all should be fine.

But back to your questions... TDS (total dissolved solids) and pH are not contaminants by themselves so these 2 parameters are not within WHO drinking water guidelines. (pH is regulated by PUB though for other reasons rather than water safety.)

In Singapore, bottled water is regulated by AVA, not PUB. (See previous post for a more comprehensive view of bottled water regulation in the world.) You can find the list of water quality parameters and requirements under AVA here. If you bother to count, the number of parameters comes up to about 30, a far cry from the ~ 200 within WHO drinking water guidelines. This essentially means that bottled water is much less tightly regulated in SG compared to tap water.

Don't get me wrong, bottled water does have its place in supplying drinking water. Especially in the early phase of an emergency/disaster, it is invaluable in providing drinking water for the beneficiaries affected by the emergency/disaster. Of course, they have little choice in the matter. If you have other choices for your drinking water, bottled water should not be the first.

Figure: A typical hot/cold/warm water dispenser linked to the water mains and incorporating water filtration

Sunday, February 03, 2019

Worried about tap water quality in an old apartment

Hi CK, 

I chanced upon your blog while searching for answer to water quality. I moved into a old apartment recently (Braddell View) and wondering if I need to invest in water filtration system (rather not as I’m renting). 

You mention in your blog that PUB does quality check of residential area. How do I get a report or know if I can drink direct from tap? The source may be ok but not sure about the aged pipes. 

Thank you for sharing your knowledge and expertise. 



Hi T,

PUB does water quality (WQ) testing of residential areas but their data have never been disclosed to the public. At best, you can get an annual WQ report from their website. However, this report does not segregate into different localities or indicate the dates/times of testing.

If you have good reason to suspect that your tap water is unsafe, you can call PUB to perform a WQ test in your residence. However, PUB will typically not reveal the results nor the tests they did except to tell you that your water is EITHER SAFE OR NOT.

The other alternative is to do your own testing but I do not recommend this unless you are pretty savvy in WQ and its testing. Even if you are, you still need the budget for the test kits or to pay a commercial lab to do the testing.

Good luck!