The average performance indicates that about 30% of the energy used for irrigation could be saved if all pumping plants operated at the Nebraska Performance Criteria. There are many causes for poor pumping plant performance. Major causes were poor power unit performance, and poor pump performance often caused by improper pump adjustment. This circular discusses proper pump adjustment to attain maximum efficiency. Both semi-open and enclosed types of turbine pumps used in irrigation can benefit from proper impeller adjustment provided enough wear has occurred to allow water to leak past the pump seals and be recirculated within the pump bowl, and that there is enough seal area remaining in the bowl to reestablish a seal by lowering the impellers.