According to Gary Slusser :

Copper (poisoning) is very harmful to humans. Pinhole leaks are very common
in copper tubing. The water damage can be in the tens of thousands of
dollars. Replumbing a house is very expensive also and the usual replacement
material is PEX, or other plastic. If the water is acidic, has high DO CO2
TDS content or anything that will cause erosion corrosion, or bacteria, or
electrical grounds problems etc., copper is not the right choice.
http://tinyurl.com/39o8w

What Gary says is true, however, I'll point out that such problems
are rare overall, corrosion mostly being a concern in some specific
areas.

I've never heard even hinted that copper pipe can be a toxicity hazard
to humans - copper is an essential mineral (in low concentrations of course)
certainly nothing even remotely close to the issue with lead solder.

Further, copper is _much_ more toxic to lower life forms than mammals.
Bare copper is rather more unlikely to harbor most bacteria than plastic is.

[There's a reason that PT lumber has copper in it...]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.