Tritium concentrations of groundwater samples from the Environmental Monitoring Program at IPEN (Institute of Nuclear and Energetic Researches), São Paulo, Brazil, covering the years 2000 to 2003, were determined by liquid scintillation counting and the results laid in the range of 20 Bq$\cdot$L-1 to 91 Bq$\cdot$L-1. The effective committed dose for general public considering the highest concentration value is 1.3 μSv$\cdot$y-1, which is below the ICRP dose limit of 1mSv$\cdot$y-1. Tritium concentration of radioactive liquid effluents samples from the IEA-R1 research reactor storage tank showed values from 3.6×103 Bq$\cdot$L-1 to 6.2×103 Bq$\cdot$L-1, approximately 1000 times below the Brazilian daily discharge limit of 3.7×106 Bq$\cdot$L-1.