A method for operating an electric submersible pumping system includes the steps of operating the electric submersible pumping system until it reaches a steady state operating condition, obtaining a first internal motor temperature measurement, obtaining a first external motor temperature measurement, and determining a first temperature differential based on the difference between the first internal motor temperature measurement and the first external motor temperature measurement. The method continues with the steps of obtaining a second internal motor temperature measurement, obtaining a second external motor temperature measurement, and determining a second temperature differential based on the difference between the second internal motor temperature measurement and the second external motor temperature measurement. Next the method includes the steps of comparing the second temperature differential to the first temperature differential, and indicating a probability of scale accumulation on the electric motor if the second temperature differential is greater than the first temperature differential.