Managing the distribution of water resources for the southern regions of Russia is of great importance in connection with limiting the consumption of fresh water. The use of saline water can lead to soil salinization and negatively affect crop production. The article deals with the problem of constructing a sequential automaton for controlling the system of switching networks when watering plants on the example of the sanatorium “Rus” in the city of Anapa, Krasnodar Territory. The Mediterranean zone, where the city of Anapa is located, is characterized by a low level of precipitation, which leads to the need for artificial irrigation of plants. The existing irrigation system using a water tank truck based on the GAZ-53 is physically outdated, which required the development of a modern automated system. The flower alleys, located on the territory of the sanatorium, were structured in a tree-like form. The construction of a control device based on rigid logic is based on the Mealy automaton. A method for constructing a control system for a tree-like water supply network has been developed, which makes it possible to control the main, distribution and supply branches. A block diagram of an irrigation machine has been developed, which has a tree-like branching, which shows control signals and states of transitions. Synthesized logical equations for the control of the water supply system, using a blocking control system with feedback. It is proposed to use the Omron programmable logic controller and CX-One software as software and hardware. The distribution of the address space of the controller is shown. Simulation modeling of the system operation was carried out, which showed the correct logic of control over the work of water pressure supply in water pipelines. Implementation of the developed system will improve the quality of irrigation of plants and minimize the cost of irrigation.