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.

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.

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: 

iwaterpurification.com/cleanwater4less-countertop-water-filter-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 

YC

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