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

There won't be many houses around with lead internal pipes

Quite a few in my experience. For people can't do DIY plumbing,
employing a plumber for a re-pipe is a huge expense. They won't do it
until the lead springs a pin-hole leak. Lots of lead pipe lurking
behind toilets, basins and baths.

And if it is completely impervious to water, why do old lead pipes
develop pin-hole leaks? It doesn't happen with copper or plastic.

- but plenty
still have lead for the incoming main.
Yes, less accessible.