Uranium is a heavy metal which is omnipresent in nature as a trace element. Solubility is high over a wide pH range in oxidising groundwater systems. In Norway, uranium in groundwater is particularly linked to granitic and gneissic aquifers. The specific radioactivity of naturally occurring uranium is rather low. Epidemiological studies indicate that long-term intake of drinking water with elevated uranium content affects the kidneys due to the chemo-toxicity of the element. A survey of 476 private bedrock boreholes in South Norway showed a median uranium concentration of 2.5 μg/l with a maximum of 750 μg/l. 12% exceeded the guideline value for drinking water of 30 μg/l set by WHO. No drinking water limit is so far defined by the European Union. A further survey of public waterworks and wells used for food production and other industries in Norway showed a median concentration, 75th percentile and maximum value for fractured crystalline aquifers of 2.04 μg, 6.8 μg and 246 μg/l, respectively (N = 346). Of these, 7.5% exceeded 30 μg/l.