• Water is purged from a well at a very low rate (100-500 ml/min)
• This reduces the stress on an aquifer and delivers ground water samples that best represent the geochemical nature of the true aquifer system
• Water quality parameters are monitored for stabilization along with drawdown in the well
• If done properly, you can create a repeatable sampling process that achieves consistent and quality results

• Improved sample quality

• Sample filtration eliminated

• Improved samlpe accuracy and precision

• Improved ability to detect and resolve contaminant distributions

• Increased well life via reduced pumping stress

• Reduced purge water volume (disposal cost)

• Reduced purging & sampling time (field labor cost)

American Society for Testing and Materials (ASTM). "Standard Practice for Low Flow Purging and Sampling for Wells and Devices Used for Ground Water Quality Investigations", ASTM D-6771-02, January 2002

Puls, R.W. and M.J. Barcelona, 1996. "Low-Flow (Minimal Drawdown) Ground Water Sampling Procedures." U.S. EPA, Ground Water Issue, Publication Number EPA/540/S-95/504, April 1996

Powell, Robert M. and Robert W. Puls, 1997. "Hitting the Bull's-Eye in Groundwater Sampling." Pollution Engineering, June 1997, pp. 50-54.

Ritchey, Joe., 2002 "Low-Flow Purging and Sampling Ground Water, Evolution of Technology and Standards" ASTM Standardization News, April 2002, pp. 18-23.

Schilling, Keith, 1995. "Low-Flow Purging Reduces Management of Contaminated Groundwater". Environmental Protection. Vol. 6, No. 12. December 1995, pp. 24-26.