EE
The 1990 NEC was the last code cycle to permit the use of
water pipe that is bonded in accordance with Section 250-80(a)
anywhere on the length of the water pipe. That was from 1990 250-50(b)exception.
The question goes to the age of the installation of the water pipe bond. Do you think it is old enough to be "grandfathered" in from the period that the 1990 NEC was enforced for the area the house you describe is in?
Al