On 18/08/2020 13:06, Mike Halmarack wrote:
The last plumber who came to fix a leak in the pipework running
through my flat said the problem would recur because between the 2
joints in the original black pipework is a section of blue plastic
pipe that is of a different diameter. The flexing of the pipework over
time causes these joints to leak. The plumber described the blue
pipework as being agricultural stuff.

That sounds like a bodge. The blue stuff is the correct pipework
for connecting a property to the mains supply, but normally just
a short length comes into the kitchen, from underground where it
connects to the house main stop cock.

Your plumber should be aware of the move from black plastic
to blue plastic pipework for water supply, because it
occurred a long time ago. The black stuff was commonly used in
the 1970's but does split with age under certain conditions.

Inside a block of flats, I'm rather surprised that there
weren't 22 mm copper risers to each flat from ground level.
Were they built this way originally, or was the black plastic
piping a retrofit ?.