In farm areas, evacuations of animal excrements (manure, liquid manure, slurry) and domestic sewage are most dangerous for pure groundwater . For betterment sanitary condition villages and pure waters in their area will be a necessity of right infrastructure and good condition (sewers, water treatments and proper animal excrements management). Research conducted in 2001–2011 in six farms located in the area of a few villages in the basin of Miedwie lake. Researches points were placed (piezometer and wells) in the area of these farms. High concentration of NH₄⁺, NO₃^- and PO₄^3- were found in a ground water which are exposed to contact inflow of pollutant from farms areas, and sources which are occurred in outlying from the source of pollutants. Also water from a farm wells, which are periodically used, manifested the presence of large chemical elements concentration, especially NO₃^- and PO₄^3-, what proves a constant inflow of pollutants. For monitoring ground water in samples we marked the concentration of NH₄⁺, NO₃^- i PO₄^3- and pH.