Why would someone's domestic water turn blue, be toxic and slippery?
I was called in to find out what was causing these problems, which made the homeowners use only bottled water in their brand new home.
After considerable investigation, including talking to several chemistry professors, I found that the cause of the problem was a combination of high pH water and bronze pipe fittings. A phenomenon called "zincification" causes the zinc in the metal compound to go into solution in the presence of his pH water. Some of the copper also goes into solution, and combines with OH molecules, forming copper hydroxide, witch is toxic, slippery, and blue. QED
Watch out for PEX pipe with brass or bronze fittings if the water has a high pH.