How can "badly installed" domestic copper pipework lead to unsafe levels of {compound of} copper in the water?

Question

I've now seen 2 reports of this on a TV consumer program, but they don't say exactly what causes it. The reports related to groups of new-builds in 2 housing estates in UK.
Apparently the developers say it is due to the residents not using enough water to keep the pipework flushed (which is obviously denied by the residents). The other reason they gave is high levels of phosphates in the water reacting with the copper, but it sounded like the water company & independant tests proved otherwise. Some residents have had to have all their pipework replaced to resolve it - but they don't say why.
Does anyone out there know what really might be causing it, because I don't like a mystery!
I always thought copper-pipe was a long-proven safe material for water transport, and it would only start to oxidize in the presence of lots of oxygen (eg the pipes were run-dry/airlocked)?

Answer 1

ABSOLUTE RUBBISH COPPER PIPE IS SAFE IN ALL CONDITIONS JUST MAKE SURE SOLDER USED WAS LEAD FREE IM SURE IT WAS

Answer 2

The level of copper could rise, if they left metal filings inside the pipe when they sanded it to get a clean surface to solder.

If you remove the aerator from the faucet and let the water run for several minutes then it should flush out the extra copper in the system.

Another consideration, I would be more concerned with would be the use of the wrong type of solder. Using lead based solder in the plumbing would increase the levels of lead and that is known to have long term hazards.

Answer 3

Overheating the pipes during the soldering process could produce oxides of copper which will gradually disolve over time, but the pipe would have to be grossly overheated.

Answer 4

Replacing the pipework fixes the problem?
Then it is either: materials, workmanship.