Groundwater quality depends on many factors, among which public water supply systems and wastewater infrastructure in built-up areas plays a very important role. Analyses of influence of designed water supply and sewage network in Maciejowa village on the ground- and surface water quality have been the main aim of the paper. A mathematical model based on deterministic description of groundwater flow and migration of pollutants has been applied. An influence of various scenarios of drinking water/wastewater system development and management on pollution loads entering water environment were simulated. Recommendations regarding the sequence of individual piping systems construction were formulated to assure the best protection of water resources.