Sudden valve closures can create rapid changes in water velocity that result in transient pressure conditions. Pressure transients can travel throughout a distribution system and cause low or negative pressures. Contamination may occur if a leak or air-vacuum valve is submerged and a low pressure wave passes through the pipeline. Pressure transients may be initiated by regular water distribution system operations. Therefore, pressure transients may occur frequently in certain water distribution systems. The objectives of this project were to verify that low and negative pressure transients...