Chlorine concentration in NEW was found to be proportional to chlorinated salt concentration used as electrolyte. In particular, 1 g/L of NaCl developed about 80 mg/L of free chlorine during 30 min of electrolysis; this concentration didn't increase during the remaining electrolysis period. The electrolysis of tap water with 15 g/L of KCl showed an increasing concentration of active clorine proportional to the electrolysis period, reaching 4000 mg/L of free chlorine after 2 h. Chlorine concentration found in electrolyzed water produced by NaHCO3 solution was not detected in line with the low concentration found by other authors (Fallanaj et al., 2013). The measurement of free chlorine concentration of tap water used for dissolving inorganic salts, was always found to be lower than 1 mg/L, so its contribute to antimicrobial activity of NEW was considered negligible