Using rainwater from a copper tank

[ferdette]

I've read that rainwater might be good to use with my about-to-be-started compost pile, and I inadvertently collect a lot of it in an old copper tank in my garden. Does anyone know if water from a copper tank, or rainwater or standing water in general, will pose problems?

[smokensqueal]

I go out of my way to get rain water or even water from my sump pump before using city water. For one it's free and it doesn't have any of the treatment checimcals that the city water does. As far as out of a copper tank I wouldn't think that would cause a problem. If I do put city water in my compost it comes from copper pipes.