The article is devoted to the lexical and semantic analysis of Chuvash hydronyms. The purpose of the study is to classify the names of water bodies by lexical and semantic groups, to identify the main principles of the nomination of hydro-names. The article deals with the names of rivers and streams, lakes and ponds, swamps and swampy places, the names of springs and wells. The main material for the analysis was collected by the author during field research, data from the toponymic file of the Scientific Archive of the CSUH and various cartographic sources, maps of land stored in rural administrations of the Chuvash Republic were used. The main methods are descriptive, comparative, typological, and statistical ones. The results of the study showed that according to the lexical and semantic classification, Chuvash hydronyms are divided into two groups: 1) hydronyms that reflect the physical and geographical properties of water bodies and their environment; 2) hydronyms that have arisen as a result of practical human activity. Most of the names of water bodies are based on a specific feature of the geographical realities themselves. Their Chuvash language can be grouped into the following subgroups: 1) names containing a significant feature of the object; 2) names indicating the ground, soil; 3) names related to the plant world; 4) names associated with the animal world; 5) names indicating the location of the water body; 6) names expressed by numerical indicators; 7) figurative and metaphorical names. Hydronyms that have arisen as a result of the practical activity of a person are divided into the following subgroups: 1) hydronyms related to the life and economic life of the population; 2) hydronyms whose meanings are related to the social life and spiritual culture of the population; 3) hydronyms derived from anthroponyms; 4) hydronyms derived from ethnonyms; 5) hydronyms derived from toponyms. It is concluded that as a result of lexical and semantic analysis, it is possible to establish the principles of the nomination of hydronymes, to identify the physical and geographical characteristics of the area, to obtain new information about the material and spiritual culture of the Chuvash people.