If site contamination is established during a phased environmental site assessment, remediation or reclamation are normally required to prevent further environmental impact. Remediation involves containment, removal, or stabilization of contaminants from soil, groundwater and vapour. Reclamation involves physical reconstruction of soils and terrain on a disturbed site to achieve equivalent land use capability as to what existed before disturbance.

An Environmental Site Assessment (ESA) is the primary tool for evaluation of environmental liabilities associated with a property. It is usually structured in phases ranging from a Phase I (historical research and site reconnaissance) to a Phase II (sampling, analyses and contaminant identification) to a Phase III (contaminant delineation).

Understanding site geology is an essential first step in any assessment of groundwater supply or contaminant migration. Hydrogeology is the combination of traditional geology with the sophisticated analytical methods required to understand and predict the complex processes involved in groundwater movement and the subsurface fate and mobility of chemical substances.