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Comment by refurb | Hacker News Reader

It seems like removal of lead pipes is overkill? Typically lead pipes develop a layer of deposits that pacify the metal, stop corrosion and prevent lead from leeching out.

The Flint water crisis was a cock-up by the water utility that resulted in loss of pacification and leeching of lead, but that a mistake that can be prevented.

Seems like regular water testing (already done) is a reasonable solution. I could see decommissioning of lead pipes (i.e. an work done needs to replace them) but a wholesale "removal all lead pipe whether or not they contribute to lead exposure" seems like overkill.

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> Following the rule's adoption, chemical engineer Abigail Cantor started testing the water after it was treated with phosphate that authorities recommended they use to prevent lead from leaching into water. But what she found was shocking.

> "[I] found that the lead increased four times over the untreated water using the highest recommended phosphate product," Cantor says.

https://www.npr.org/2016/03/31/472567733/avoiding-a-future-c...

Even with biofilm-protected lead pipes, you still need to flush the system, by letting the water run for a minute or three, before you drink it.

Lead pacification results in a layer of insoluble material on the interior surface of the pipe so that the drinking water doesn't contact lead. It's typically done at the source - at the drinking water plant.

It can result in undetectable levels of lead in the water, despite the pipes being made of lead.

This summarizes the chemistry quite nicely: https://www.acs.org/education/resources/highschool/chemmatte...

There is no need to "flush" the water, because it doesn't contain any lead.

It is probably wise to flush though as unless you have tested recently you have no idea if the lead protection is working. My own home (70 years old) recently failed lead tests (3 samples with ranges 14-45 μg/L) that we had to request from the city. Otherwise we would have had no idea.

I agree that testing is key if there is a risk of lead exposure.

This is part of the reason why engineers in antiquity always explicitly favored hard water when choosing the headwaters to route aqueducts from.

> Typically lead pipes develop a layer of deposits that pacify the metal, stop corrosion and prevent lead from leeching out.

Was going to come here to say this. Saying that, old pipes do need to eventually be replaced. But I wouldn’t freak out if you have lead pipe running into your house, especially no new ones have been installed for many decades.

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