Hacker News Reader

Comment by morsch | Hacker News Reader

It'd be interesting to know how much chlorine, if any, is added to make the tap water potable. There are many places in the world where it's perfectly safe to drink the tap water, but not pleasant.

View on HN

When I was travelling in Canada I was checking if the water was safe to drink. And the government website argued it was safe to drink tapwater precisely because it was purified with the help of chlorine. In Netherlands many of us have the opposite view that it's not safe to drink tapwater if there is chlorine in it (let alone the taste). Interesting contrasts in cultures :)

I think you may have misunderstood. It is pretty standard to use chlorine in the purification process, but that chlorine is not left in the water. There should be negligible chlorine in any water coming out of the tap. I've certainly never been able to smell it let alone taste it anywhere in Canada.

Maybe Canada is an exception, but in most places the chlorine is left in the water because the distribution network isn't entirely sterile.

Missed the Canada part. Canada likely has very pure water from snow melt.

So half a year they have to get it from north or preserve in sterile tanks? :) I live near Urals above 99% of Canadians and there is no snow for 6 months.

An example, San Francisco historically got it's water from the Hetch Hetchy Reservoir. It's all from alpine snow melt and springs. Used to not be chlorinated because it's organic content is very low. I assume a lot of Canada is the same.

https://en.wikipedia.org/wiki/O'Shaughnessy_Dam_(California)

Most Ontario Canada's water is from the great lakes

There is more precipitation during a warmer half of the year on their territory outside of ocean shores where it's in reverse, also the gap between those grows further to north.

There is residual chlorine or today more likely chloroamine in tap water. Part of the reason for that is to keep pathogens from growing in the pipes. Though depending on season and basic water quality there may be none.

If you care, ascorbic acid or one of it's salts line sodium ascorbate reduces[1] chlorine and chloroamine. Takes just a tiny amount, works instantly.

[1] Chlorine -> chloride. chloroamine-> chloride + NH3.

I could have misunderstood! But when you can smell it when you shower and taste it when you drink it, there is a considerable amount of residue of chemicals in the water. Maybe I smell it because I'm used to water without it. I don't know if it's actually harmful, but when there are alternatives widely deployed, for instance in the Netherlands I don't see the reason for taking the risk.

Lake Ontario (Canada) water definitely has some chlorine taste/smell, but you get used to it and it is perfectly safe.

Canada is a very large country with a wide variety of water. I'm quite surprised that you were somewhere where you were able to smell/taste chlorine in the water as that has not been my experience, but at least one other commenter seems to agree with you. That said, small amounts of chlorine are perfectly safe.

I grew up in a city where chlorine is not used. In Canada, and almost every other country I've lived in, I can clearly taste the chlorine in the water, while locals always insisted it was tasteless.

This is a rather common effect. Does a lot of police on the streets make you feel safe or unsafe? There are obvious and opposite arguments for both possible answers.

In general, the taste of tap water in The Netherlands is better than in for example Belgium. Both have the same rating (and both are safe, not just as tasteful). Mind there are be locational differences in taste, water in Gent (BE) tastes better than in Kortrijk (BE) and water in Arnhem (NL) better than in Amsterdam (NL).

That's indeed interesting! Chlorine in the tap water seems to be one of the major factors why people buy bottled water, even though otherwise it might be perfectly healthy.

Reply on news.ycombinator.com