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Copper contamination in domestic rainwater collection system

We have a problem that no one we have spoken to has experienced previously. We have been able to access 'glimmers' of detail on copper contamination, but all without any veracity or strength of premise. Our situation is as follows:

High levels of copper have been found in the rainwater collected for domestic useage for roof surfaces. The roofing material is zinc aluminum (Colorbond) and the gutters are box gutters coated with an acrylic waterproofing material. The primary collection system from the box gutters is via large copper downpipes into water tanks.

There have been several theories posed for the copper contamination. They include: water softness increases the opportunity for copper leaching to occur; water sitting for extended periods in copper pipes within the system exacerbates the copper leaching; electrolysis between the two different metals of the roof materials and the copper downpipes results in copper contamination of the water supply.

Water testing has been done and we continue to test to try to isolate the problem. However, have any of you heard or such a situation, or have experience with these problems and subsequent solutions?

Any help is sincerely appreciated.

Christine Marsden
Domestic builder - Noosa Heads, Queensland, Australia
March 3, 2008

I have a galvanized steel roof and copper gutters and downspouts. They do not touch anywhere to minimize glavanic corrosion. I have noticed that the grass has died at the downspouts. Could this be due to copper contamination?

Karl Hesse
- Huntersville, North Carolina
March 15, 2008