Nowadays electrochemical disinfection has gained increasing attention as an alternative for conventional drinking water disinfection, because it is regarded as environmentally friendly, amendable to automation, inexpensive, easily operated and is known to inactivate a wide variety of microorganisms from bacteria to viruses and algae. If compared with chlorination (the use of gaseous chlorine or concentrated hypochlorite solution), no addition of chemicals is necessary, because the main disinfecting agents are produced from the naturally occurring ions found in the water itself. It was determined that, if electrolysis of solution with constant concentration of chloride ions is done, the amount of released chlorine increases with extending the time of electrolysis. After about 15 minutes of water electrolysis no cultivable E. coli was detected in the samples (5 log decrease) and after 2 hours no metabolic activity of the cells was observed anymore if chloride ions are present in the concentration range, which is common in tap water, the electrolysis process using TiO2-x electrodes can create enough amount of active chlorine to kill more than 99% of E. coli within 15 minutes.