The ability to predict the time when to stop a SVE system is critical when designing and operating a SVE remediation system. Completed research on the tailing performance of SVE, allowed the development of the closure time index (CTI) concept. CTI is based on breakthrough curves for both lab-scale experiments and a field-scale application of SVE. Application of the CTI concept allows estimation of the time when the SVE system could be shutdown. Shutting down a SVE system at the appropriate time minimizes operational time and reduces clean-up costs as demonstrated by the field case data that was tested.