1.1 This test method specifies the operational parameters required to grow a reproducible (1)2 Pseudomonas aeruginosa ATCC 700888 biofilm under high shear. The resulting biofilm is representative of generalized situations where biofilm exists under high shear rather than being representative of one particular environment. 1.2 This test method uses the Centers for Disease Control and Prevention (CDC) Biofilm Reactor. The CDC Biofilm Reactor is a continuously stirred tank reactor (CSTR) with high wall shear. Although it was originally designed to model a potable water system for the evaluation of Legionella pneumophila (2), the reactor is versatile and may also be used for growing and/or characterizing biofilm of varying species (3-5). 1.3 This test method describes how to sample and analyze biofilm for viable cells. Biofilm population density is recorded as log10 colony forming units per surface area. 1.4