Ground Water Summit registrants may enroll in these short courses held in conjunction with the event for an additional fee. This short course provides the tools to determine if you really have metals contamination in groundwater or surface water at your site. Trace-element adsorption on specific suspended particulates (e.g., clays, iron oxides) is well known. Under oxidizing, circumneutral pH conditions, this adsorption affinity typically yields positive correlations between trace elements versus aluminum or iron. These relationships are visualized with scatter plots of trace versus major element concentrations. Consistent elemental ratios are observed for uncontaminated samples; contaminated samples are identified by anomalously high elemental ratios. Other important factors are pH, redox effects, aqueous complexation, and salinity gradients. In contrast to purely statistical approaches, geochemical evaluations reduce false-positive declarations of contamination, do not require statistically valid background data sets, and provide mechanistic explanations for elevated concentrations. Insightful case studies are presented from numerous sites across the U.S. This course is recommended for regulatory personnel as well as consultants and site managers.