An apparatus and method for measuring metal corrosion rate in solutions, including solutions having low ionic strength. Three electrodes including a counterelectrode, a reference electrode, and a working metal electrode are dispossed in close proximity to each other and an ion conducting, but electrically insulating, material is provided between at least the reference and working metal electrodes. The ion conducting material provides a pathway for ions to travel between the electrodes other than through the solution without also creating a short circuit between the elctrodes.