Current Measurement on Water Line

[kwired]

I'm new here and it's my first post. I'm wondering if you have a subpanel in the house that happens to have the ground and neutral bonded again and you are measuring a neutral current going through your grounds?

That is a fine suggestion, but if he indeed did turn everything off and still had current on the water line, then the current on the water line has to be coming from outside the home.