Just my 2 cents. Is there an underground utility transformer on the property? That happened here in my neck of the woods. We feel that the fault lies with the POCO. Their primary cable is leaking current into the earth. The way we found it was that the EC disconnected the meter and there was still voltage on the water pipe. He also disconnected the telco and the CATV. He still had voltage. ( about 10 volts) One last thing to look for, any plastic water filters? They might need to be bonded.
