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Would be kind of funny if humanity went this way:

Lead pipes -> cast iron pipes -> copper pipes -> plastic pipes -> copper pipes

I always run the water in the bathroom and kitchen until it's super cold, letting me know I've gotten to the stuff fresh out of the main. But I was trained to do this because when I was a kid we had some lead pipes in our home, heh.
"But I was trained to do this because when I was a kid we had some lead pipes in our home, heh."

There were no lead water pipes in our home but lead pipes were used to couple gas meters to iron pipes presumably to make installation easier. What was worrying was that all the street water mains were made of asbestos cement.

Decades ago, when I first traveled to France to visit relatives I noticed that all the water plumbing in their home was lead.

When I commenced on it and the dangers they thought I was a little eccentric and commented that that was the norm in that area of Paris and no one had become sick from the lead pipes.

My only comment is that my French cousins who are roughly the same age as I am are much smarter than me. (Pb is supposed to dull the brains of kids so what went wrong here?)

Lead water pipes get coated with minerals in the water, especially in areas with hard water. Once this happens they are "safe" to use.
Unless the water doesn't have the appropriate corrosion inhibitors, like what happened in Flint. Then it'll leech out. It's common that it will be coated in minerals, but it's no guarantee.
It would be very informative to compare the chemical composition of the water in Flint with that as I described in Paris. The immediate observation is that with Flint the Pb was already in the water, presumably with Paris the supply was clean (or comparatively so) and the only chance for it to get into the water would be household pipes.

Clearly the French weren't overly concerned about it. Like most of the EU they overregulate everything and presumably would have mandated the pipes be changed if they thought them a problem.

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So it seems like the theory is that it is specifically rubber seals found in plumbing fixturse that are leaking the additives into the water? It does beg the question whether or not something like pex or press-fit copper pipes (with the rubber o-rings) also leaks additives. The researches also say the additives could come from tire pollution.
I wonder why plumbing fixture gaskets are so often made of natural rubber or other apparently utterly crappy rubber. They tend to degrade quite badly and often fail if they are disturbed if they’re not brand new.

EPDM is slightly more expensive in bulk than natural rubber and would (I expect) last a lot longer. Yet even an EPDM garden hose washer seems to be rare.

I noticed recently when repairing my taps that rubber seals had degraded and touching them left black sludge on my hands
> In previous research, Shane Snyder and Mauricius Marques dos Santos found that these rubber additives can react with disinfectants in simulated drinking water. Their lab tests generated a variety of chlorinated compounds

The actual problem: chlorine

Chlorine kills things - it's why they put it in the water, but it is not completely benign to people, and can have all kinds of unintended interactions with other materials.

We ended up moving to a home with a well due to health issues with chlorine. UV light provides safer and effective sanitization.

It's amazing how much longer toilet tank parts and other plumbing materials last when not exposed to chlorine.

I've had the suspicion that a lot of chemicals are leaking into the water because plumbing is an old enough field that there's a lot of "that's how we always did it".. If you've ever sniffed at new plumbing supplies, you're not doubting that they will leak something, after all, if something has a smell, it's giving off something to its surroundings. My principles when drinking tap water is to let it run until cool and never use warm water for drinking or eating.