A method measuring a rate of fouling caused by a heat flux through the surface subjected to electrochemical polarization. The method includes the steps of: providing a piezoelectric microbalance comprising a piezoelectric material with electrodes disposed thereon; exposing the working electrode of the microbalance to a flowing liquid, the liquid containing at least one fouling forming species; maintaining the liquid at a constant first temperature; maintaining the liquid at required hydrodynamic conditions; applying either a constant heat flux through the microbalance resulting in its working electrode having a variable second temperature or applying a variable heat flux through the microbalance resulting in its working electrode having a constant second temperature; and measuring a rate of fouling on the microbalance surface. The method also comprises measuring the surface density and heat transfer resistance of the deposit independently, thereby the corresponding ratio can be determined contributing to the deposit identification. The working electrode of the microbalance can be subjected to an electrochemical polarization in a wide range to systematically simulate the conditions of heat exchange surface produced by corrosion or other electrochemical processes. The possibility to apply electrochemical polarization, cooling or heating flux in the direction opposite to that causing fouling can be used to clean the immersed microbalance surface in-situ.