The authors of the article studied the rivers and lakes of the Leningrad region of the North-West region of the Russian Federation for the total iron content and analyzed the results obtained. This chemical indicator is being investigated due to the fact that it can have an adverse effect on the environment and human health. The main goal of the work was to analyze the most polluted water bodies of the Leningrad region in terms of excess of the maximum permissible concentration (MPC) for total iron and to develop a way to reduce its concentration. A colorimetric analysis method was used to obtain the data. Exceeding the maximum permissible concentration for total iron was found in more than 80% of samples. A detailed analysis of the three most polluted water bodies was carried out. The results obtained showed that the water bodies of the Leningrad region are heavily contaminated with common iron. In this regard, it is required to develop special measures to reduce its concentration. The authors suggest the use of gabion structure with a special filler for bank stabilization and reduction of the concentration of total iron to the most polluted rivers of the Leningrad region.