The second-generation Eurocodes, in particular EN 1990 and EN 1997, will rely more heavily on reliability and probability approaches for design (and verification) of geotechnical structures and for treating available data. The determination of groundwater levels will be based on concepts like annual probability of exceedance or fraction of time exceeded. When groundwater time series are available, the required groundwater levels can be determined using statistical analysis. In this paper we illustrate assessing the various groundwater levels values using extreme value statistics for real life data sets, highlighting pitfalls and providing practical recommendations for geotechnical practitioners. To that end, we address the selection of probability distributions, processing of the data to obtain annual extreme values and sanity checks of the results.@en