The search of new methods for water teatment a ety for both humans and animals (including a bird) is an urgent and important problem today. The purpose of the work is to investigate the effect of drinking water with the use of probiotic bacteria B. licheniformis and B. subtilis on the rats. Experiments were conducted on three-month-old male non-linear laboratory rats with an average body weight of 153.9±2.4 g. There were 15 rats each in the experimental and control groups. For 3 months, the rats of the control group were fed with water taken from a well ("buvette"), the rats of the experimental group were fed with the same water, but passed through a filter with immobilized probiotic bacteria Bacillus licheniformis UKM-5514 and Bacillus subtilis UKM B-5007. Probiotic bacteria have been found to suppress other water microbiota. The positive effect of drinking water with probiotic bacteria in rats was established. In the rats of the research group, already after 1 month of drinking water with probiotic bacteria, the appetite and the condition of the fur, which became thicker and more shiny, compared to the control, improved. An increase in their mass was noted in the experimental group after 2 months by 9%, after 3 – by 12% compared to the control. The content of hemoglobin, total protein and alkaline phosphatase increased in experimental rats. According to the results of pathologicalanatomical and histological studies, the control and experimental animals did not differ from each other. Scientific novelty. A "Ukrainian modification" of "English filters" is proposed, which consists in creating a biofilm of probiotic bacteria on sludge (sand, coal, etc.). This method of water treatment rids it of existing microorganisms and enriches the filtered water with probiotic bacteria, which can be used in animal husbandry, poultry farming, and for the purification of tap drinking water.