Electric submersible pumps (ESPs) historically have had short run lives. Their failures usually were unexplained and accepted as the norm. Because the equipment has generally been downhole, finding all the influences that shorted equipment life expectancy has been difficult. Horizontal surface installations for water injection have been made where machine operating conditions could be monitored and equipment performance analyzed. Unbalanced pump vibration has been identified as the cause of many seal problems and ultimately motor and pump failures. In fact, excessive vibration appears to be an inherent mechanical characteristic of ESPs. To illustrate the severity of this problem, this paper presents data gathered from field installations with monitoring equipment, from equipment tear-down analysis, and from statistics on ESP failure modes.