Water jet impinging heat transfer is widely used in steel-making industry, nucleate power plants, and many other applications. In this study, an experimental study was carried out in an industry-scale facility. In this test facility, an insulating material was added to simplify the heat-transfer process. The data filter method was used to remove the noise in temperature measurements. Using inverse heat conduction analysis, surface heat flux was obtained, and the inverse heat conduction method was verified. The relative error between the calculated and measured temperature at the bottom surface of the test plate was less than 5%, and the relative error of the inner temperature of the test plate was less than 0.35%. Increasing the surface roughness provided better heat transfer in the stagnation region, which is in agreement with the reported results in the literature. By determining the surface temperature of the test plate, the boiling heat-transfer mode can be identified.