Flint's is a member of the Karegnondi Water Authority. They'll know about the pipelines. They probably have old records.

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That is the best place to start. They are not responsible for the poisoning. Please recall the pipelines were safe before Snyder took over. The pipes could concrete or steel. I'd think we can be sure the folks at this water authority can help put the puzzle pieces together. It is good place to start.