A method and system is disclosed for testing a cathodic protection system that protects a metallic structure with one or more DC power sources electrically connected to the metallic structure and an associated reference electrode. The metallic structure may be cathodically protected at multiple locations. A Cathodic Protection Waveform Monitoring Unit (CPWMU) operates independently from power cycling by the cathodic protection system to measure cathodic protection voltage levels by measuring, over one or more measurement time periods, a voltage differential between the metallic structure and its associated reference electrode, a plurality of times when power provided to the metallic structure is cycled on and off. The CPWMU includes digital storage to store values indicative of the measured voltage differentials over the measurement time period. A Cathodic Protection Waveform Reader (CPWR) that may be remotely located from any CPWMU communicates with a number of CPWMU's within communication range to obtain the values stored in the CPWMUs. The CPWR may be positioned in a variety of aircraft, vehicles or be hand carried.