Abstract: The aim of this study was to investigate the sonolysis of water microorganisms. Ultrasound waves as a disinfection technology at a frequency 42 kHz was used to inactivation of indicator microorganisms of water like the Escherichia coli (E. coli), Clostridium perfringense (Cp) and Heterotrophic Plate Counts (HPC). In ultrasound technology, the phenomena of cavitation which involves formation, growth and violent collapse of vapor bubbles in a liquid media is known to generate a high intensity pressure which affects the microorganisms viability. Therefore, ultrasound waves display a strong influence on the rate of microorganisms inactivation in aqueous suspension. Results showed a significant increase in sonolysis for indicators with increasing duration of sonication time in the 42 kHz. Sonolysis in 42 kHz is capable to some degree of inactivation indicator microorganisms. On the other hand, more than 99% of microorganisms was inactivated within 90 min.