[en] There has been an increasing concern with the assessment of human exposure to naturally occurring radionuclides as they account for around 70% of the total dose received by the population. Most of the exposure derived from natural terrestrial sources comes from the radionuclides in the uranium series, which is headed by the long-lived isotope ²³⁸U. Radionuclides pertaining to this decay chain, such as, ²²⁶Ra, ²²²Ra, ²¹⁰Pb and ²¹⁰Po are the most important to be studied, as far as the dose to the population is concerned. In order to verify if the levels of radioactive contaminants in the water from public supplies are in compliance with the limits set by the Ministry of Health, a survey has been carried out in the metropolitan area of Recife, Brazil. This paper reports the results of this survey for both, superficial and groundwater supplies. Water samples collected from 107 sampling points were analyzed to determine their content of natural uranium, ²²⁶Ra, ²²²Ra, ²¹⁰Pb and ²¹⁰Po. Uranium concentrations were determined by fluorimetry after extraction with an organic solvent and deposition in LiF/NaF pellets, which were fused at 1000degC. Radium-226 was determined by the emanation technique, whereas ²²²Rn was determined by liquid scintillation counting. Polonium-210, on the other hand, was determined by alpha spectrometry, following its spontaneous plating in copper disks immersed in the water samples. Measured concentrations ranged from 43 to 1330 mBq/L for natural uranium, 5.3 to 83.7 Bq/L for ²²²Rn and from below the MDL (22 mBq/L) to 337 mBq/L for ²¹⁰Po. The annual intake of each radionuclide was calculated by considering an ingestion of 2L of water per day. The dose to each organ considered important to the ingestion pathway was calculated by using the masses given in the ICRP 23 for the standard man and by applying the appropriate dose conversion factors. (author)