COPPER CORROSION

[consruct1]

IN THE PROCESS OF REMODELING A HOME,ALL NEW PLUMBING.
THE PIPING WILL BE PEX AND THE FITTINGS ARE COPPER,
A WATER TREATMENT COMPANY HAS SAID THAT THE WATER WAS TO ACIDIC AND THAT I NEED A $3,500
TREATMENT SYSTEM TO CORRECT OR THE PIPES(FITTINGS)
WOULD FAIL. MY QUESTION IS AT WHAT POINT(PH)WILL
COPPER START TO DETERIORATE?

 

[kenvlach]

While the corrosion of copper will also vary with the water's hardness, oxygen content, CO2 content, Fe, sulfide, etc., a pH of 7.4 is the minimum I would tolerate. A pH of 7.8 is what public utilities often use.
To see how the solubility of Cu varies with pH, see

http://www.finishing.com/Library/metalpH.html

What treatment method are you considering?
My corrosion handbook mentions treatment with lime or sodium silicate.