1.1 This guide covers methods for purging wells used for ground water quality investigations and monitoring programs. These methods could be used for other types of programs but are not addressed in this guide. 1.2 This guide applies only to wells sampled at the wellhead. 1.3 This standard describes seven methods (A-G) for the selection of purging methods. Method A—Fixed Volume Purging, Method B—Purging Based on Stabilization of Indicator Parameters, Method C—Purging Based on Stabilization of Target Analytes, Method D—Purging Based on Fixed Volume Combined with Indicator Parameter Stabilization, Method E—Low Flow/Low Volume (Minimal Drawdown) Purging, Method F—Well Evacuation Purging, and Method G—Use of Packers in Purging. 1.4