Wednesday, August 31, 2022

 Hi Mr Chen

I saw your blog after researching on hard water in Singapore.  I also read your reply a few years back on hard water.

 I just want to share that i just moved to a new flat and the water is indeed hard. My kettle, sink, shower glass and toilet bowl are all impacted. They come back in 2 days.

 While i have asked PUB to do a water test, my suspicions is that they will tell me "it's within safety standards".

 But i am concerned about impact to appliances, pipes and taps, not to mention the constant need to remove deposits.

 In my FB post to a group, it seems like west area has this issue, though mine is central area and my flat is built in 2006. 

 Anyway, i just want to 

 1. share with you that there's hard water in SG.  

 2. Get your advise if i should get a ion exchange filter.




Hi BT,


Here are my thoughts.


You are refer to the latest copy of PUB's Water Quality Report here.  First, hardness is not a safety concern in drinking water. Therefore, there is no WHO guideline or EPH (Environmental Public Health) regulation for it. Technically, PUB does not even have to test for hardness in your water sample. In the report, total hardness was assigned an average of 39mg/L and a range of 19-157mg/L. As mentioned before in this blog, there is no mention in the report of when, where and frequency of sampling with regards to these figures so do take them with a wide, open mind. Another obvious point is the deviation of total hardness from its average value seems rather broad so your tap water can still fall within the range near the upper limit and it is still acceptable.


 In countries like USA where hard water is often encountered, house owners install POE (point-of-entry) filters to remove hardness at the point at which water enters the house. (As you rightly commented, these are often based on ion exchange.) Hence, all fixtures in the house will not be exposed to hard water. This may be impractical in a SG flat due to cost and space. In fact, I have not heard of any residence here installing a POE filtration system.


The alternative is a POU (point-of-use) filter that is typically connected to the tap where you obtain your drinking water. Of course, this does not address the issue of your piping and fixtures being exposed to hard water. Also, as mentioned before in this blog, unless you are particular about the taste of your beverages (coffee, tea etc.), a POU filter is redundant. (Commercial coffee joints do install these as the quality of their beverages is important to them and their customers.) 


Lastly, you may want to test your water just to be sure that it is indeed hard. Either purchase a DIY kit or send a water sample to a commercial testing lab. The DIY kit should be cheaper if you are testing for a single water quality parameter. If you are opting to test for a package of various water quality parameters, the commercial lab should prove to be more competitive.


 Good luck!

Premium Water Hardness Test Kit | Fast and Accurate Hard Water Quality  Testing Strips for Water Softener Dishwasher Well Spa Pool, etc. | 0-425  ppm | Calcium and Magnesium Total Hardness (150 Strips) : Garden 

Figure: A simple DIY water hardness test kit on Amazon (No, I am not an affiliate.) 

Monday, May 31, 2021

Removing fluoride and chlorine from tap water

After my interview by CNA, some questions came in about the removal of chlorine and fluoride from tap water. 


Unlike other substances in tap water, chlorine and fluoride are added into tap water by the water treatment process. Chlorine is supposed to keep water free of pathogens as the water is conveyed from the water treatment through kilometres of piping (with many other equipment in between) to your home. On the other hand, fluoride is supposed to maintain dental health as the locals here tend to have tooth decay issues in the years after independence. I have written about chlorine and fluoride previously - fluoride & other contaminants in beer, Do we really need water filters?, Evaluating the necessity and usefulness of water filters for domestic tap water, Advice on water filtration in Singapore: alumina, boiling, gravity fed vs. counter-top.

 In recent years, much health concerns have been raised about these 2 additives in our drinking water. Are they safe at the concentrations in tap water? Are they even necessary? As with a lot of health issues, there are arguments on both sides. A lot of times, it comes down to the consumer to decide on getting a water filtration system to remove them for good, old peace of mind. To me, this is perfectly fine as I can attest to the importance of peace of mind from personal experience. What I do have issue with is the selection of an effective water filtration system (aka water filter), if one even exists.

3 points to consider in selecting a water filter

Those who have watched my interview with CNA (CNA has somehow left out these 3 points in their print version) should recall that I have expressed 3 factors to consider in getting a water filter.
  1. Know what you want to remove (or add) from your water.
  2. Find a water filter certified to remove those contaminants
  3. Make sure you can spare the time and money for maintenance

A more comprehensive guide can be found in my article - 3 Critical Questions to Choosing Your Water Filter which can be downloaded for free.

Which water filter can remove chlorine and fluoride then?

Some readers have mentioned their confusion by the vast assortment of water filters in the market. Without going into laborious scientific research, are there any water filters that I can recommend to remove chlorine and fluoride? 


In general, most brands of water filters do not show certification from a reputable source e.g. NSF/ANSI. Furthermore, they do not display evidence of extensive testing of their filters either. Most claims to remove this contaminant and that pollutant are just that - claims.

Naturally, quite a few brands have slick marketing campaigns and impressive designs. In fact, their designs can actually be aesthetically pleasant and functional in piping tap water under the sink to a sleek looking but unobtrusive faucet on the tabletop. However, the question still remains - can the filter perform the job you want it to - removing chlorine and fluoride from tap water? In the majority of cases, I am not confident enough to say they are capable of it.

But I still want a water filter for peace of mind

Yes, I understand the importance of peace of mind so I shall make a recommendation here. 


I strongly suggest getting a Big Berkey fitted with their Black Berkey filter elements + fluoride reduction attachments. (No links provided here. I am sure you can find it easily on the Internet.) Though not actually certified by NSF/ANSI, their filters are extensively tested under NSF/ANSI standards and the detailed results with testing protocols are published on their website. That is a lot more than what the majority of brands can provide to the consumer.


Nevertheless, a caveat is in order - NSF/ANSI standards are not exactly Singapore tap water standards. The most obvious difference is Singapore's tap water has chlorine and fluoride in much lower concentrations. How much can a filter further reduce their concentrations? We did tests on certain water filters in the past and the reduction is in general not fantastic. And unfortunately, Singapore is too small a market for anyone to actually conduct testing of water filters for their effectiveness in treating Singapore tap water.

With that in mind, dear consumer, go ahead and choose your water filter!

Figure: Big Berkey replacement filter elements

Should you boil your tap water?

After my interview by CNA, some questions came in about the necessity of boiling tap water. 

Are there benefits to it? Does boiling mitigate the effects of contaminants from piping and water tanks?

  1. First off, let's be clear that boiling water has been a tradition in Singapore for a long time, probably dating to before independence, and for good reasons. In the old days, not everyone had access to tap water. Whatever water sources (rivers, ponds, wells) in those days were probably low in sanitary standards, if any. Imagine someone bathing and defecating into the river that you obtain your drinking water from. Piping and water tanks were probably poorly maintained.

    This combination of conditions were recipes for outbreaks of water borne diseases like cholera, dysentery etc. The main culprits were of course pathogenic microbes transmitted via contaminated water and food. The good news is such microbes can be killed by boiling. As long the boiled water does not get recontaminated, you are safe from these nasty water borne diseases with colourful nicknames like bloody diarrhea or rice water-like stools. Not surprisingly, boiling water has become a standard practice that persists even after every household on the mainland is served by tap water.

    Check out this post by Rice Media: A brief history of lao sai, explained if you want to get down and dirty for the details.

  2.  However... boiling does nothing to the rest of the non-microbial contaminants in the tap water. If your piping and water tanks are rusty, rust will go into your tap water. Not that rust is a real health concern, it is just that boiling does not remove it. Neither does boiling remove heavy metals, pesticides or most radioactive substances. It certainly does not remove fluoride (hey, we need fluoride to REMAIN in the water for healthy teeth, remember?) and only removes a small percentage of chlorine.

  3. Is boiling necessary then?

    If we go by the study by CNA of which my interview is part of the programme, the bacteria count is either undetected or low in the tap water. Please keep in mind that these bacteria are probably harmless. Of course, if you are concerned about the maintenance of the water tanks, equipment and piping leading to your household, by all means, go ahead and boil your tap water. Maintenance is ultimately performed by humans and there is always a possibility of human error.

    As mentioned above, if you decide to boil your water, make sure your boiled water does not become recontaminated in whatever container you are using. 
Figure: Boiling water in this vintage kettle from the old days