This study is the second phase of a two-year effort to determine the effects that sampling tubings have on organic analyte concentrations. In the first year, 20 different tubings were compared, under static conditions, with respect to sorption of organic contaminants and leaching of organic constituents. In this study, we examined what occurs under dynamic conditions when TCE-contaminated water is pumped through several different types of polymeric tubings. Sorption of organic solutes, leaching of organic constituents, and desorption of sorbed organic contaminants were all examined. Five tubings were selected for this study: a rigid fluoropolymer, a flexible fluoropolymer, low-density polyethylene (LDPE), and two plasticized polypropylene tubings. These materials were selected because our static studies had shown that these tubings leached little or no organic constituents (as determined by HPLC analyses with an ultraviolet UV detector) and ranged from being the least sorptive tubings tested to among the most highly sorptive. The effects of tubing length and flow rate were examined. Results from these studies indicate that if water is pumped through tubing at a slow flow rate (100 mL/min), fluoropolymers should be used to prevent extensive losses of TCE and more sorptive analytes, especially if the tubing is 50 ft or longer. If a faster flow rate (1 L/min) is used, it appears that LDPE tubing can be used to sample TCE and other less sorptive analytes, although time for equilibration (2% hr) should be allowed to reduce losses in the deepest wells.