Presentation discussing the adverse effects of air on force mains and pressurized pipes. Causes, effects and prevention are discussed. Presentation includes two anecdotal stories about the two major destructive issues that occur with air on pressurized lines: waterfall flow and air slam. This presentation was given at the operator appreciation conference at TDEC Fleming Training center in 2023 and I would like to continue to provide some options for operators to gain knowledge about system operation issues. Presenters: PJ Ashford, Jon Ward, and Taylor Ross, Metro Water Services