The article describes a method for measuring radial force using a measurement system employing strain gauges bonded to the shaft, as well as the calibration method for this system. Using this approach, three different types of impellers were investigated: a standard multi-blade enclosed impeller for clean water, a vortex impeller for contaminated liquids, and a two-blade impeller with a large free passage. To achieve similar hydraulic parameters, a modified impeller diameter and rotational speed were used, resulting in an error below 8% in the range of 300 to 600 m3/h. The Q-H and Q-η characteristics were determined. Measurements of average radial forces as a function of flow rate and instantaneous radial force as a function of impeller rotation for all three impellers are presented. The multi-blade enclosed impeller was characterized by the lowest average radial force, which was 265 N at a flow rate of 260 m3/h. The average radial forces of the vortex impeller were 139%, and the two-blade impeller 185% of the forces of the multi-blade impeller, and were obtained for 340 and 300 m3/h, respectively. The largest difference between the flow rate of minimum radial forces and the best efficiency point occurs for the multi-blade enclosed impeller, where the minimum radial forces occur at a flow rate of 63% of the optimal flow rate. The presented force measurement system enables the performance of numerous tests, particularly important for single-blade and two-blade impellers.