The basis for ensuring the safe operation of hydraulic structures is facility monitoring systems. The introduction of software tools for diagnostic modelling of filtration flows into the software of such systems is an objective step caused by recent real-life events. The aim of this study is to improve the accuracy of existing methods for numerical modelling of two-dimensional stationary filtration flows using the mesh method in the software of the facility monitoring system. The methods used in the study included the mesh method, the finite difference method, as well as approximation methods and numerical algorithms. As a result of the study, it was found that the proposed method of organizing the iterative computing process was effective and useful. Its application can significantly reduce the complexity of software development, as it is based on the formalization and standardization of operations, which simplifies the programming process. In addition, the use of conventional loop statements makes the process of writing programmes more understandable and accessible to developers. The additional array used in the algorithm allows easily changing the configuration of the grid boundaries and the order of operations for each node, which makes the method flexible and suitable for various challenges. A special advantage of the algorithm is its logical simplicity, which contributes to successful adaptation in the case of using multiprocessor systems. Thus, the results of the study confirm the high efficiency and potential of the proposed method for use in practical computing tasks. The proposed method of iterative computation is of considerable practical importance in the field of software development for numerical modelling, since its use simplifies the programming process and provides flexibility in working with different problem conditions, which makes it an important tool for a wide range of research and practical applications in hydraulic engineering and related fields