The multifunctional waste water and ground source heat pump system includes a sewage system (1), a waste water treatment unit (2), an inspection manhole (3) for the cleaned waste water, an accumulation container (4), a ground collector (6), a heat pump (7), heating, hot water and cooling systems (8), whereby the accumulation container has been designed for equalizing the daily cyclical waste water amounts, reducing the area of ground heat collector, increasing water temperature in utility systems, and the use of fire fighting and irrigation water.