[weinzierl]

I cannot add to my post above, but since people don't seem to take it well, I'd like to add some data to back it up.

Here is the link to a paper that compared contaminants in drinking water in various developed countries. When it comes to residual chlorine the USA demonstrated the highest levels followed by Singapore and Canada. After these three countries there was a huge gap before the UK and other countries which much lower levels.

Could it be that you are all so used to the chlorine, that you don't notice it anymore?

https://www.researchgate.net/publication/343719890_Comparati...

In addition, here is the WHO list of countries ranked by access to safe drinking water. The US is number 42 after Bulgaria and Guadeloupe.

https://en.m.wikipedia.org/wiki/List_of_countries_by_access_...

[radlad]

From your first link, Table 1, I see that the United States EPA regulates chlorine to 0.2-4 mg/L. The upper bound is lower than the rest of countries with regulations. Some countries - including the European Union, United Kingdom, and Ireland - appear to have no regulations at all.

Residual levels show 3 mg/L of chlorine in the United States which is higher than most other countries (Singapore, and to a lesser extent, Canada, excluded.) What I don't understand is why you see these levels, which are considered safe by most health agencies, as a cause for concern. As another commenter pointed out, the chlorine exists to ensure the water is safe to drink.

[weinzierl]

"From your first link, Table 1, I see that the United States EPA regulates chlorine to 0.2-4 mg/L. The upper bound is lower than the rest of countries with regulations. Some countries - including the European Union, United Kingdom, and Ireland - appear to have no regulations at all."

The European Union is not a country and it is not surprising that it has no guideline, because the member states have. That the United Kingdom and Ireland are similar to the US is not surprising. I could not find a source for the value of 5 mg/l for Germany, most sources say 0,3 mg/l but the actual text of the current law doesn't corroborate that. What it does is strictly regulate the reaction products of chlorine, which makes sense from a health standpoint.

"Residual levels show 3 mg/L of chlorine in the United States which is higher than most other countries (Singapore, and to a lesser extent, Canada, excluded.)"

I am not a native English speaker, so forgive me if I read this wrong, but the paper says of all the considered countries the US has higher residual chlorine levels than all the other countries (Singapore, and to a lesser extent, Canada, included)

In other words US is highest, followed by Singapore and then Canada.

"As another commenter pointed out, the chlorine exists to ensure the water is safe to drink."

As the paper shows most developed countries have safe drinking water without chlorine. So the question is not why I am against it but why the US needs it in the first place .

[radlad]

No, the question is very much why you are against it when your claim is apparently that the water is not safe to drink because of it.

[weinzierl]

Safety is always a trade-off. If I am in an area with cholera epidemic I gladly will consider the chlorine in my drinking water safe. Where I live the water is clean and adding chlorine does make it definitely less safe.

Chlorine is a very hazardous substance after all.

According to the CDC the TLV for chlorine is 1.5 mg/m3. Note, that this is per cubic meter and not per liter. So a TLV of 0,0015 mg/l vs 4 mg/l in US drinking water.

https://www.cdc.gov/niosh/idlh/7782505.html

And here the definition of TLV from Wikipedia:

The threshold limit value (TLV) is a level of occupational exposure to a hazardous substance where it is believed that nearly all healthy workers can repeatedly experience at or below this level of exposure without adverse effects.

[radlad]

The TLV you cherry picked refers to concentration in breathable air, not drinking water.

Most health authorities agree that chlorine is safe at 4 mg/l.

Ultimately proactive and reactive approaches both have pros and cons. But implying levels of chlorine in US drinking water are unsafe has no scientific backing.

[weinzierl]

"The TLV you cherry picked refers to concentration in breathable air, not drinking water."

Chlorine is a gas. I started this subthread with my claim that I always experienced a smell of chlorine in American tap water. Now the threshold to smell chlorine is 3 ppm while the TLV is 0.5 ppm. In other words, when you can smell it is already way above the TLV.

But it is even worse: While chlorine is absorbed when ingested, this is a lesser problem. Copyed from my comment above: "Chlorine forms compounds with organic substances (the microorganisms it kills) in the water, which in turn can be toxic or carcinogenic. Instead of regulating the (volatile) chlorine it makes much more sense to regulate the harmful compounds, which is exactly what many European countries do."

"Most health authorities agree that chlorine is safe at 4 mg/l."

Authorities agree that chlorine is safer than dying from the pathogens in dirty water. We all agree on that. If you have the choice of dying from cholera next week or bladder cancer in 15 years, you sure will pick the cancer. (Yes, there is a link between chlorinated drinking water and bladder as well as colorectal cancer).

Safety is always a trade-off and the EPA's task is to find a compromise [1]. That is where the 4 mg/l come from. Other authorities and organizations have different priorities, which result in different thresholds. For example, The International Botteled Water Association limits chlorine in botteled water to 0.1 mg/l. In Germany, the level for water in swimming pools is 0.3 mg/l. And by the the way the current SDWA encourages alternate treatment methods too.

Ultimately proactive and reactive approaches both have pros and cons. But implying levels of chlorine in US drinking water are unsafe has no scientific backing.

It is not about proactive and reactive approaches. That point is that with clean drinking water chlorine is unneccessary as evidenced by all developed countries except the US, Sinagpore and Canada.

[1] "EPA must conduct a thorough cost-benefit analysis for every new standard to determine whether the benefits of a drinking water standard justify the costs." https://en.wikipedia.org/wiki/Safe_Drinking_Water_Act

[stonogo]

I don't think that WHO list is particularly useful. Included in the numbers of "people without access to safe drinking water" is everyone who draws from a well or a spring. The US is huge and well water is extremely common in rural areas; most well-water users have their own in-house water treatment equipment. Nevertheless they'd be classified as not having access to an improved water source under this survey.