Modeling is a very useful tool in the investigation and remediation of contaminated sites, that is generally misunderstood and underutilized. Often, modeling is perceived as requiring protracted and expensive efforts, beyond the means of most projects. However, developing a clear set of objectives and understanding the limitations of each modeling effort enables us to develop the information that needed and to obtain regulatory closure. We are providing examples of how the application of these principles allows to obtain valuable results expending only modest effort and cost.