Does KDF-55 add copper to my drinking water? Isn't too much copper bad for you?
This answer requires a little background.
KDF-55 is a mixture of Zinc and Copper, as certain impurities are removed from the water, Zinc and Copper ions are released.
Zinc and Copper are both essential minerals for the human body, however it is possible for some people to get too much copper, because a small percentage of the population retains copper. Getting too much zinc on a modern diet isn't likely at all.
Now to the answer, and the good news: the amount of zinc and copper added to your water by KDF-55 is insignificant.
Here is part of a test report from an independent lab, which was commissioned by the makers of KDF (emphasis added):
Sample 2 contained water that had been eluted through the KDF column prior to inoculation and there is substantial die-off of the bacteria compared to the control water. This die-off is very likely due to small amounts of copper and zinc ions that are eluted (less than 0.025 ppm copper and less than 1ppm zinc). This result is not unexpected since it is well documented that copper is toxic to bacteria.
You can read the entire report here: http://www.kdfft.com/lab_biological.htm