The article provides information on issues related to the decrease in potable water, which is currently the most pressing, about methods of water treatment without harm to health, namely using biological methods such as water purification with the help of high and low aquatic plants, as well as information on the possibilities of reusing purified waters. Recommendations are given for the use in agriculture of biomass from aquatic plants. The main research object is the “National Water Supply Company in Karakalpakstan.” Water for treatment was taken from drinking water sources. Pistia (Pistia stratiotes L.) is considered a perennial annual aquatic plant, its leaf length is 10-12 cm, and width is 6-8 cm. Lemna minor L. is relatively small, its leaves and fronds are tubular in shape, with a length of 2-4 mm and a width of 2-3 mm. Chlorella vulgaris, Lemna minor. L., and Pistia stratiotes. L. are bred in fish ponds, enzymes that counteract pathogenic microorganisms such as bacteria, viruses, and fungi are produced in water and destroy pathogenic microorganisms. Chlorella vulgaris increases oxygen content in fish ponds by 30-40%, meaning it emits 200 times more oxygen from its biomass.