The paper presents analysis of reasons of catastrophes caused by errors in planning, realization and exploitation of dams based on the case of the catastrophe of the earth dam in Gorow Itawecki which happened in the year 2000. On the basis of information gained from the provincial building supervision inspector in Olsztyn there has been presented characteristic of 15 dams situated on the area of the Warmia-Mazurian Province -their catastrophe may threaten the life of people or cause significant material losses. It is indispensably to carry on register of all dams in Poland and in particular provinces, to carry on periodic evaluations of the technical state and safety and to secure financial means for repair and modernization of those objects. If the mentioned above actions are not undertaken the catastrophes of small dams similar to that one in Gorow Itewecki may happen in the near future.