The block maxima and peak over threshold approaches to extremes have been applied to pitting corrosion data from laboratory-simulated buried line pipe steel. Both approaches have been useful for gaining a better understanding of pitting in low carbon steel. We show that the parent distribution of the extreme depths is the right tail of the observed pit depth distribution. The threshold approach proved more robust to maximum depth reduction, which results from the dependency between pit depths. A simplified sampling method is proposed for applying the threshold approach without the need for measuring the entire pit depth distribution. © 2008 Elsevier Ltd. All rights reserved.