27

Are there any health issues with drinking heavily chlorinated water?

During a recent trip to Australia (Queensland, NSW), virtually all tap water I found had a very strong chlorine smell and taste. I asked locals and was told it is safe to drink and I did not get any adverse effects after drinking it for a week.

I am curious, because in other places I lived (Switzerland, Singapore), tap water does not smell at all and chlorine smell is usually linked to swimming pools or decorative water fountains which carry a "do not drink" sign.

4
  • 1
    Is this really on-topic? It's not really about traveling...
    – Flimzy
    Feb 19, 2014 at 15:56
  • 8
    I think it is, as this is probably a question other travellers will come across.
    – drat
    Feb 19, 2014 at 16:10
  • 2
    Travelers come across all sorts of questions which aren't on-topic here. :)
    – Flimzy
    Feb 19, 2014 at 16:14
  • It may be the case that "chlorine smell" is not really chlorine, but chloramine: chlorine.americanchemistry.com/Science-Center/…
    – Χpẘ
    Jul 27, 2017 at 18:54

5 Answers 5

22

My understanding is that chlorine, in the concentrations found in drinking water, does not pose an acute health danger. There may be health risks associated with long-term exposure, and this is a more controversial topic, where the literature and expert opinions are mixed. Most main-stream information seems to suggest it's safe, but the skeptics claim a corporate bias, etc.

Some of the long-term exposure risks reported are cancer, heart trouble, and senility. Note that much of claimed risk is associated with long, hot showers, not drinking it.

If you're only visiting for a while, and don't have any known Chlorine sensitivities, you'll probably be just fine. If the taste bothers you, or you're especially concerned about long-term health affects, drink bottled water.

Some related SE posts:

24

The other answerers have answered your question about whether it is safe. I'd like to address the issue of chlorinated water not being very pleasant to drink by explaining how to dechlorinate the chlorinated water.

You can reduce that chloriney taste somewhat, mainly by aerating the water. I kept tropical fish for years and you can't use chlorinated water in a fish tank because it will poison the fish (it's used for killing bacteria and germs, after all). Special dechlorinating chemicals are sold for this purpose (I'd not recommend you use them as they're designed for fish tanks not human consumption), but there is another way: let the water stand for 24 hours and the chlorine will evaporate. This should remove the chloriney taste.

If you want to do it more quickly, or you don't want the water to taste stale (which could be worse than the chlorine taste in some people's opinion), just aerate the water as much as you can. Get two big glasses and pour it from one to the other back and forth for a little while. The more you air it, the less chlorine it will contain and hence the less chloriney it will taste.

As I'm sure you realise, removing the chlorine won't remove the germ-killing effects that the chlorine had as those effects have already taken place, so it will still be safe to drink from that perspective.

1
  • 3
    or boil the water and then chill it again Feb 19, 2014 at 11:51
11

Yes.

The chlorine is put in there exactly in order to make it safe to drink by killing germs. If tap water is not chlorinated, it can mean one of two things:

  • either the place has no regulations concerning germ counts in tap water and whether it's safe to drink is basically up to luck.
  • or there are such regulations and the water provider is able to ensure that the source of the water is germ free (typically deep wells or mountain springs) and the delivery infrastructure preserves this.

Countries where water quality is regulated typically require constant checks and chlorination when and if germ counts rise above safe levels. This can be necessary constantly in regions where the only available water is from rivers, or temporarily when there is contamination somewhere in the system.

Swimming pools and decorative fountains are chlorinated because the water there is constantly contaminated from outside.

8
  • 6
    If there is no chlorine smell it can also mean, that the water is cleaned by UV light and active coal filters. At least in Czech Republic it's used in some facilities.
    – jnovacho
    Feb 19, 2014 at 11:08
  • 5
    For a fuller answer, I think this should address whether the water is unsafe because of the chlorine, not just whether it's unsafe because of germs. (The question is broad enough that the OP might also be worried about drinking what is, essentially, a poison.) Feb 19, 2014 at 11:37
  • 2
    @starsplusplus: One should note that "strong, displeasing smell", "unswallowable", "burning mucosa", and "poisonous" are all phenomenons of chlorine, which are each 2-3 orders of magnitude apart in dose.
    – Damon
    Feb 19, 2014 at 16:15
  • @Damon The issue isn't whether I think that it's safe or not. I simply mentioned that that's included in the scope of the OP's question. If you're saying it is safe, then post that as an answer. Feb 19, 2014 at 16:20
  • @Damon Upon rereading your comment, it sounds like you might be complaining about my use of the word "poison"? From Wikipedia: poisons are "substances that cause disturbances to organisms". The reason the chlorine is there is to kill bacteria and germs - it's therefore acting as a poison. My choice of words was not intended to imply anything about its effect on humans, just that the OP might be inquiring as to said effect. Feb 19, 2014 at 16:23
7

Yes it is.

It is just a matter of taste (not the best obviously).

I have been drinking water like this for years in Barcelona and various parts of Greece where it is very common.

But the main reason I say it is safe is this:

I have been walking the GR11 route, the one that does all the pyrenees from Barcelona coast (more or less) to the Basque Country in Spain. During this walk (40 days) I had chlorine tablets that obviously give it a not so popular taste. I was fine!

So yeah go on and drink. You can find other tablets that take the taste off the chlorine but I would not mess with even more chemicals.

5

Yes, the water is safe to drink.

Drinking water is purified at a Water Treatment Works (WTW) using one of a variety of methods, and if everyone drank directly from the outflow of the works there would be no need for the chlorine. However, the water then has to travel, sometimes for several days and tens or even hundreds of kilometres, along pipes before it reaches the consumer. These pipes are never perfectly clean — they contain a mixture of old pipe fragments (iron, cement), silt, and bacteria stuck to their walls — and the chlorine is necessary to keep the drinking water sterile while it travels.

Whether or not you can taste the chlorine depends on a number of factors: your distance from the WTW (the chlorine decays over time), the condition of the pipes (and thus how much chlorine is necessary to keep the water safe), and whether the water company uses chlorine, with a strong taste, or monochloramine, a related chemical that performs much the same task but has less taste.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .