Environmental site assessments (ESAs) are needed for most transfers of property and are usually required by most lenders such as banks or mortgage companies. The purpose of an ESA is to evaluate the degree of environmental liability (generally soil or groundwater contamination) that may be associated with a property. Regulations that make ESAs a necessary condition vary from state to state (in the USA). Often the degree or complexity of an ESA is determined by the lender rather than by the regulatory agency. If contamination is found at concentrations that exceed regulatory standards, then the state regulations dictate what must be done to achieve compliance. Typically ESAs include the following tasks:

• File research to evaluate past usage and potential for contamination

• Site inspection and interview(s) with person(s) familiar with the property and usage

• Research into ownership and past ownership of the property

• Subsurface investigation, usually involving either test drilling or microprobes/micro wells

• Headspace screening of soil samples obtained during drilling/probing for volatile organic compounds

• Field and laboratory analyses of soil and groundwater samples

• Elevation survey of wellheads to facilitate groundwater depth and gradient mapping

• Evaluation of all data and preparation of ESA report with conclusions and recommendations