Most of our planet is occupied by waters of oceans, seas, lakes, rivers, ice. Even clouds are accumulations of water. Once, long ago, all life on earth originated in the ocean. Water is needed by plants and animals. The employees of the Zakamskiy Territorial Administration of the Ministry of Ecology of the Republic of Tatarstan conducted an environmental lesson at Sarmanovskiy secondary school on this topic. The purpose of the lesson is environmental education of the younger generation, expanding the horizons of schoolchildren.