The validity of remote earth reference cell placement when conducting structure-to-soil potential
measurements of buried cathodically protected structures is a poorly understood and controversial
subject. This paper will present cathodic protection test data conducted by the regulatory staff of the
Mississippi Department of Environmental Quality of over one thousand underground storage tanks that
were surveyed utilizing both local and remote earth reference cell placement. Factors that can affect
the potentials observed when obtaining local and remote earth reference cell placement are discussed.
Empirical data are presented comparing and contrasting the relationship between the local and the
remote earth potential. The data suggests that the information derived from remote earth locations
when conducting structure-to-soil potential surveys of underground storage tanks deserves further
consideration than that which has traditionally been afforded. In addition, this paper presents
fundamental concepts of cathodic protection testing intended as a plain language explanation for a
general audience of laypersons who may not be familiar with the intricacies of testing cathodic
protection.