Site investigations and remedial actions generate large amounts of data. While tabulating the data is necessary for the purpose of satisfying reporting requirements and comparisons to standards, it does not allow us to understand and explore relationships in the data to obtain important information on items such as contaminant source or fate and transport. Data visualization tools allow us to explore and understand these relationships. However, application of these tools requires planning and proper selection of assumptions, to avoid reaching improper conclusions. We are providing examples of how simple tools provide powerful information for site closure.