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This paper specifically discusses the natural radioactivity in drinking water due to uranium isotopes in three towns located in the uranifferous Copperbelt region in Zambia.Uranium is naturally occurring radioactive material present in certain types of rocks and soils.Water passing through and over rock and soil formations dissolves many compound and minerals,including uranium; so vary amounts of it are present in some water resources.Higher values of uranium in drinking water and foodstuffs may lead to harmful effects like kidney damage,leukaemia and cancer in human beings.According to estimate,food contributes about 15% of ingested uranium while drinking water contributes about 85%.Drinking water samples were collected from municipal water taps in Kitwe,Chambeshi and Chingola towns over a period of five (5) months in 2009.The samples were analysed for uranium isotopes using Canberra Alpha Analyst Spectrometer at the Nuclear Energy Cooperation (NECSA) in South Africa.The average summed activity concentrations for U-234,U-235,and U-238 isotopes are expressed in milliBecquerel per litre (mBq/1).Chambeshi township water under Nkana Water and Sewage Company Limited abstracting water from Chambeshi underground mines had the highest activity concentration of 600.78 mBq/L followed by Roberts Reservoir of Mulonga Water and Sewage Company Limited abstracting water from the Kafue River in Chingola with 188.14 mBq/L.Bulangililo Water Treatment Plant abstracting water from Kafue River in Kitwe had 152.68 mBq/L while Nkana East Water Treatment Plant also abstracting water from the Kafue River in Kitwe had 139.64 mBq/L.A1 Reservoir of Mulonga Water and Sewage Company Limited abstracting water from both Kafue River and Konkola Copper Mines (KCM) underground had 77.16 mBq/L while the least was Garnetone township with 78.50 mBq/L abstracting water from Mwambashi River,a tributary of Kafue River in Kitwe.The average summed annual effective doses were 20.81μSv/y for Chambeshi,6.48μSv/y for Roberts Reservoir,5.25μSv/y for Bulangililo,4.82μSv/y for KCM Al Reservoir,3.78μSv/y for Nkana East and 2.63μSv/y for Mwambashi.Chambeshi Township had a highest summed annual effective dose of 20.81μSv/y but below the World Health Organization (WHO) recommended guidelines (2004) of Reference Dose Level is 100μSv from 1 year s consumption of drinking water but it is above the recommended screening levels for drinking water of 500 mBq/L for alpha emitters activity,therefore,qualifies for routine screening for radioactivity.