The paper presents an assessment of the impact of sewage treatment plants with drainage system on the quality of groundwater in dug and deep wells in the Kwasówka village in the municipality of Drelów (Lublin Province). In the study area there is no sewerage system and water supply, and the local population benefits from dug or deep wells. The wastewater generated by households goes to septic tanks or sewage treatment plants with drainage system. The study of groundwater quality from wells was performed in 2013. The study was performed 4 series of studies, during which determined: total hardness, pH and conductivity of the electrolyte, as well as the content of NO3, NO2, NH4, Cl, SO4, Fe, Mn and bacteria from coliform and faecal coliform bacteria, mesophilic and psychrophilic. The research shows that water from deep wells are heavily contaminated with iron, and several wells dug reported exceeding the permissible concentrations of ammonia, nitrate, manganese and sulfates. Microbiological studies indicate a significant contamination of the well water analyzed domestic waste. You should immediately take action to improve the quality of the water used by residents of Kwasówka.