How safe is our drinking water?

How safe is our drinking water is a profoundly important yet controversial and difficult topic; whilst chlorine can remove the bugs it also introduces toxic THMs.

Fibreglass rainwater tank.

This page was last updated on 2nd April, 2021.

Chlorination is arguably one of the greatest breakthroughs in public health; cholera and typhoid deaths, and other waterborne diseases have virtually been eliminated in the developed world.

It has another great benefit over other means of disinfecting public drinking water; there is a residual effect that continues in the reticulation, destroying bacterial pathogens.

Yet still today over three million young children die every year in the developing world from waterborne bugs where proper reticulation and sanitisation does not exist.

There is a new realisation that the friendly bacteria in the gut play an extremely important role in the prevention of non-communicable diseases. Questions are being asked whether this residual influence of chlorine may have a significant antibiotic effect on the so-called microbiome that lives in the gastrointestinal tracts of humans.

Numerous animal studies suggest that, at the level of chlorine in our water, it is safe to drink; remember the stomach has large amounts of the acid anyway. However, there are still no studies to date that evaluate any possible toxic effect of that residual chemical on the microbiome that inhabits the gut.

Of greater concern though is the effect of chlorine in our water reticulation on organic material forming toxic trihalomethanes (THMs) that cause bladder tumours and other problems like miscarriages.

You may have read in the media that Cape Town’s water currently has an earthy taste[1]; it is due to high levels of organic material from the Voëlvlei Dam. Despite assurances from the authorities that it is safe to drink, residents are rightly concerned.

These findings, plus the large amount of plastic particles in our drinking water, create great difficulties for those concerned about their wellness. Are we becoming neurotic, on the verge of what is known as orthorexia? It is a pathological worry about right-eating and drinking; a first cousin to better known anorexia.

For me it is just one more reason we are so pleased to have built an underground reservoir which stores the rainwater we have harvested from the roof; that will certainly have some organic material from the gutters but, in the absence of chlorine, no THMs are formed. We have a happier microbiome and there is the certainty of no plastic being ingested.

There is little or no risk of waterborne bacteria like E.Coli, and even amoeba from faecal material, but it would be safer to boil it if one intends to drink it.

Of course, since the beginning of time, humans have been drinking rainwater.

Non-nutritive sweeteners

Non-nutritive sweeteners like NutraSweet, Sweet One, Sween'N Low are passed unchanged into the urine; they are frequently being found in boreholes, groundwater and sewerage treatment plants.

Researchers have already shown that toxic sweeteners are causing urinary bladder tumours and glucose intolerance leading to diabetes.

In addition, researchers have now shown that they increase the transfer of antibiotic resistant genes between the bacteria in our gut[2]. Already nearly a million people worldwide die from these bacteria for which there is no known treatment, and it is estimated to rise more than 10 times in the next 30 years.


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How safe is our drinking water?

Our complete reservoir for collecting our drinking water.

How safe is our drinking water is a question we should all be asking.

Many people do not drink any water these days in the Western world and that is part of the vexing question. On the other hand the added sugar and chemical sweeteners are even more dangerous for our well-being than the chlorine and even perhaps the THMs.

  1. Bernard Preston
  2. Rainwater harvesting model
  3. How safe is our drinking water?
  1.  Cape Town's earthy-tasting water is safe to drink, says city.
  2. Nonnutritive sweeteners can promote the dissemination of antibiotic resistance through conjugative gene transfer. Web:

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