Health, Health Tips, Things We Use (And Love!)
comments 2

Is Chlorine Safe In Our Drinking Water?

The focus on drinking water has been to eliminate pathogens, and with good reason. According to a study conducted by the Natural Resources Defense Council, more than 120 million people (about 50% of the population) may get unsafe water  for consumption. Hence, chlorination of drinking water significantly reduced mortality rates associated with waterborne pathogen.

However, research is starting to reveal the risks of over-chlorination. For example, some have claimed that a substantial portion of the cancer risk associated with drinking chlorinated water; duration of exposure to chlorinated surface water was associated with bladder cancer risk among women and nonsmokers of both sexes. (1)  Research from the University of Nijmegen in the Netherlands discovered that people who swam in chlorinated pools or polluted waters as children had 2.2 to 2.4 times the risk of developing melanoma compared to those who did not swim in chlorinated waters. (2)

“Chlorination of water rich in organic material is known to produce a complex mixture of organochlorine compounds, including mutagenic and carcinogenic substances. A historical cohort study of 621,431 persons living in 56 towns in Finland was conducted in order to assess the relation between historical exposure to drinking water mutagenicity and cancer…a statistically significant excess risk was observed for women in cancers of the bladder (relative risk [RR] =1.48, 95 percent confidence interval [CI] = 1.01-2.18), rectum (RR = 1.38, CI= 1.03-1.85), esophagus (RR = 1.90, CI = 1.02-3.52), and breast (RR = 1.11,CI = 1.01-1.22).” – Cancer Causes & Control (3)

“The cancer risk to people who drink chlorinated water is 93 percent higher than those who don’t” — U.S. Council of Environmental Quality

What exactly is chlorine?  Chlorine, # 17 on the Periodic Table of Elements, is, by itself, a yellow-green poisonous gas.  Chlorine poisoning occurs when someone swallows or breathes in (inhales) chlorine. See all the symptoms of chlorine poisoning here. Chlorine was also the first poison gas to be used as a weapon during World War I. (4)

“Because of the corrosive effect chlorine had on organic matter, it was used as a horrendously effective weapon during World War One. By nature, the gas, which is heavier than air, stayed close to the ground and destroyed the soldier’s lungs.” —

You can call me paranoid, but after my mum’s cancer recovery experience, I would rather be safe than sorry so we opted for a water distiller to clean our drinking water at home. I even changed my mum’s shower head to ensure the water she bathes in is chlorine free!

I put my water distiller to the stress test by using a chlorine meter:

Distilled Water - Before

Tap Water – Before distillation (Chlorine level – 97/ppm)

Distilled Water - After

Distilled Water – After. (Chlorine level = 0/ppm)!

Distillation not only gets rid of chlorine. It removes up to 99.9% of most tap water contaminants.

Residue after 1 round of distillation! Eww. Distillation not only gets rid of chlorine. It removes up to 99.9% of most tap water contaminants.

On top of chlorine, these are the test results from using a Total Dissolved Solids Scanner (TDScan). “Total Dissolved Solids (TDS) are the compounds in the water that cannot be removed by a traditional filter. TDS are made up of salts or compounds which dissociate in water to form ions…Total Dissolved Solids are classified as a secondary contaminant by the Environmental Protection Agency (EPA) and a suggested maximum is 500 ppm.” – (5)

Tap Water – 350ppm
Filtered Water – 340ppm
Distilled Water – 000ppm

Tap Water - 350 on TDScan meter

Tap Water – 350 on TDScan meter

Filtered Water - 340 on TDScan meter

Filtered Water – 340 on TDScan meter

Distilled Water - 000 on TDScan meter

Distilled Water – 000 on TDScan meter

To reveal what unseen metals/impurities may be in the tap water we are drinking, we used a water electrolyzer. How it works is that when we pass an electric current through a solution, ions (charged particles) migrate towards the electrode of the opposite charge. For explanation sake, assume there is a salt in the water, and the dominant species of ions are sodium (Na+) and chloride (Cl-). So when we apply a current to the solution using electrodes, the chloride ions (Cl-), termed anions, will move towards the positive electrode (the anode), whilst the positively-charged sodium ions (the cations) will migrate towards the negative electrode (the cathode). The migrating ions carry charge through the solution and hence help to complete the circuit. At the anode, 2 chloride ions (Cl-) will each surrender an electron to the anode to form a molecule of chlorine gas to form bubbles: 2Cl-(aq) -> Cl2(g) + 2e-. At the same time, the any solution metals will also try to donate electrons e.g. if there is copper in the tap water, Cu(s) -> 2e- + Cu2+(aq), forming copper ion (Cu2+) which then goes into solution, turning the water bluish green.

In this case, we do not know what metals are in the water but there are many substances turning the tap water a smelt gross brown/green mix after electrolysis, while the distilled water stayed clear till the end of the experiment.

Performing water electrolysis on tap water vs distilled water

Performing water electrolysis on tap water vs distilled water


Residue after performing water electrolysis on tap water

Having traveled to developing countries where I couldn’t even get clean tap water to bathe in, I am really thankful for the relatively clean water we have that most of us can drink from the tap and not have a stomachache immeditely! But since distillers are relatively affordable (I got my distiller for SGD$518) and lasts a long time, I have added this additional regimen of distilling the water so my family can have the benefit of having water free from bacteria and viruses (killed by the chlorine), and we then remove the impurities (via distillation).

Read more about the water distiller we use for drinking water, and the shower head we use to reduce chlorine exposure!


1 –
2 – Department of Medical Informatics and Epidemiology, University of Nijmegen, The Netherlands. Melanoma Research (Impact Factor: 2.52). 11/1994; 4(5):281-6. DOI: 10.1097/00008390-199410000-00002. Source: PubMed
3 – Cancer Causes & Control, 1997, Volume 8, Issue 2, pp 192-200. Drinking water chlorination and cancer – a historical cohort study in Finland by Meri Koivusalo, Eero Pukkala, Terttu Vartiainen, Jouni J.K. Jaakkola, Timo Hakulinen
4 –
5 –

Feature image credit:



  1. Pingback: Getting rid of Chlorine exposure in your showers! | Eat | Pray | Fly -ing

  2. Pingback: Water Distiller: Purwa Water Distiller | Eat | Pray | Fly -ing

Leave a Reply

Your email address will not be published. Required fields are marked *