A corrosion sensor includes a plurality of metal strips having different thicknesses. A first metal strip with the least thickness is first employed to provide sensitive corrosion detection. After an exposed portion of the first metal strip is consumed, a second metal strip having a second least thickness can be employed to provide continued sensitive corrosion detection employing a remaining un-corroded portion of the second metal strip. The plurality of metal strips can be sequentially employed as exposed portions of thinner metal strips become unusable through complete corrosion and un-corroded exposed portions of thicker metal strips become thin enough to provide sensitive corrosion detection.