Radon gas is a significant health threat linked to thousands of preventable deaths each year. In this research, radon concentrations are measured in 136tap water samples collected from 34different places of Baghdad city, Iraq, using the electronic radon detector RAD-7 (Durridge Co., USA). The results of radon concentration varies from (0.012) to (0.283) Bq/L with a mean value of (0.111) Bq/L. The annual effective dose in Ingestion (stomach) and Inhalation (lungs) per person for children and

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... t is also calculated. The total annual effective dose of children and adults were (5.676) and (2.838) µSv/y respectively. At last may be concluded, the results of radon concentrations and annual effective dose in all samples show no significant radiological risk for the inhabitants in the reign study.