Results of ground waters analysis, which as one of the most precious abiotic elements of the environment are under special protection, were presented in the work. Long-term research results included 2 water intakes "Park" and "Motława" in Tczew (northern Poland) consisting of 19 operational openings taking water from three water-bearing layers: Cretaceous (4), Teritary (10) and 5 Teritary-Cretaceous. Low content of NO2 (from 0,000 mg/dm-3 NO2 to 0,043 mg/dm-3 NO2) and NO3 (from 0,09 mg/dm-3 NO3 to 0,26 mg/dm-3 NO3) was found, placing lower than the NDS obligatory standards. Ammonia content (NH4+) turned out differently. Its content in raw water in general depiction of every water intake was characterized by overrunning the NDS standards. Fluorides in waters are a separate problem, the concentration of which was between 0,28 to 2,80mg/dm-3 F at the highest concentration allowable (NDS) equaling 1,5 mg/dm-3. It wasproved that 38% of samples over run the quality standards. It was noted that the highest fluorides' concentration level was present in waters taken from water-bearing Cretaceous levels down to 150 m. Mixing the waters coming from different water-bearing layers turned out to be a sufficient procedure for getting good quality water with optimum fluorides' concentration.