Is the old riser pipe rusty? If yes, I suspect the leak is either the plug or through the pipe wall. Just a pin hole leak or two thru the pipe wall could easily provide 1 GPM flow. If the mystery water is flowing thru an old rusty pipe, that could explain the iron level being higher in the mystery flow.

Last edited by Bill D.; 03/08/17 06:43 PM. Reason: Clarification
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