Radon (Rn-222) concentration was determined in selected 27 tap water samples collected during autumn and winter seasons in 2012 around city of Konya, Turkey. While 11 tap water samples were taken from dwellings with water reservoir, other tap water samples were taken from dwellings without water reservoir. Radon measurements were performed by an AlphaGUARD radon gas analyzer. All determined the mean radon concentrations for the autumn and winter seasons were found to be 3.15 Bq l^-1 for the samples collected from dwellings with water reservoir and 10.20 Bq l^-1 for the samples collected from dwellings without water reservoir. The calculated effective doses for ingestion were 0.17 for minimum and 3.67 μSv a^-1 for maximum and for inhalation of radon in indoor air caused by these waters 2.18 μSv a^-1 for minimum and 45.84 μSv a^-1 for maximum.