In this study we describe the use of acoustic time-domain reflectometry (TDR), and complimentary signal processing for direct measurement of inorganic fouling in a reverse-osmosis desalination system. The sophisticated acoustic measurement system consists of a 8-bit, 200 MHz digital oscilloscope interfaced with 486 PC for real-time data acquisition and analysis. The experimental RO system employed is capable of accurate automated measurement and control of process variables including feed concentration, operating temperature and pressures, and axial flow rate. The RO cell utilized is 64 cm long with a rectangular geometry and has six permeation ports; three 5 MHz and three 10 MHz acoustic transducers are externally mounted on the top surface of the RO cell for continuous acoustic TDR measurement at points which correspond to each of the ports. Computer-controlled and multiplexed measurements of acoustic signals, permeation rates, and permeate concentrations from each of the ports allow precise monitoring of fouling phenomena via conventional permeation rate-decline behaviour as well as the acoustic TDR response. We present here the results of a comprehensive set of experiments in which axial flow-rate was systematically varied and the resulting effect on the fouling process was investigated. The experimental results generally showed a close correspondence between the permeation and acoustic TDR measurements. A significant drop in the permeation rate and acoustic signal amplitude observed for axial flow rates of 150 ml/min and 0 ml/min was attributed to the occurrence of fouling based upon subsequent optical and scanning electron microscopy analysis. For experiments employing the 330 ml/min flow rate, a substantial decline in the permeation rate was observed as well; however, the acoustic TDR measurements did not indicate the presence of a fouling layer. Microscopic analyses confirmed this latter observation. Consequently, acoustic TDR appears more sensitive than inferences from permeation flux measurement with respect to the occurrence of inorganic fouling. Inorganic fouling process and acoustic wave scattering from the fouling layer can be well modeled and simulated using fractal growth concepts. In this paper we shall present results of unified modeling and simulation of the two diverse phenomena using fractal concepts.