The article represent the use of disinfectant which was made based on salts of polyhexamethylene guanidine hydrochloride (PGMG-hydrochloride) and polyhexamethylene guanidine phosphate (PGMG-phosphate) for water disinfection. Water plays one of the most important roles in almost all life processes. Water is a part of the blood, participates in blood circulatory system, delivers nutrients and oxygen to the organs, participates in oxidation reaction, hydrolysis and other reactions of intercellular metabolism, forms an environment to maintain a healthy microflora of the digestive tract, which provides effective breakdown of nutrients by the optimal amount of enzymes.
 Good drinking water quality must to be epidemically safe and free of pathogenic microbes, viruses and other biological inclusions. Also must be harmless in chemical composition, have good organoleptic properties ‒ be transparent, colorless, have no taste or odor.
 Water quality is assessed by total microbial contamination and the amount of bacteria of the Escherichia coli group in 1 cm3 of water, and also by thermostable Escherichia coli (fecal coliforms) in 100 cm3 of water, pathogenic microorganisms and the amount of coli-phages.
 In result of the conducted researches it was found that the use of disinfectant in 0,2 % concentration did not reduce the total microbial pollution of water. In particular, the efficiency of 1, 2 and 3-hour of exposure was 57, 62 and 68 %, respectively.
 After application of disinfectant in 0,3 % concentration the efficiency of its application was for 1 h – 69 %, 2 h – 82 %, 3 h – 100 %.
 It was found that the use of a disinfectant, which was made based on PGMG salts in 0,4 % concentration contributed to reduce the total microbial contamination of water. The efficiency by the 1, 2 and 3 hour of exposure was, respectively, 73, 86 and 100 %.
 Therefore, the use of a disinfectant, containing in its composition PGMG salts, in 0,3% concentration at 3 hours of exposure was more optimal, which contributed to reduce the total microbial contamination of water.