On 3 Jun, 18:49, "Dave Plowman (News)" wrote:

There won't be many houses around with lead internal pipes - but plenty
still have lead for the incoming main.

PS; I meant lead/tin soldered copper pipe, rather than lead.

The fact remains, there is no legal acceptable lower-limit for lead
ingestion and lead solder has been banned for potable water use
(meaning all H&C services) for yonks.
The builder can still be held liable for the replacement costs,
assuming they're still in business.