A fuel leakage detection system for an underground fuel piping system having fuel service pits installed at locations along the piping. Each pit has a pressure sensor and a reference electrode positioned external to the pit assembly for continuous and automatic monitoring of fuel pressure and pipe-to-soil potential measurements of an impressed current cathodic protection (ICCP), and each pit assembly includes a processor and a transceiver. The system provides simultaneous and synchronized pressure and ICCP potential measurements which are transmitted over a wireless network to a control station that performs accurate location of a leakage point in the underground piping and can detect pressure loss during fueling operations which produce strong pressure transients that normally mask detection of pressure loss in the fuel piping, and can determine a leak in the piping and its location by analyzing the pipe-to-soil potentials taken on the fuel piping and pressure losses occurring between transients.