A total of 25 well water samples from various locations of Idah and environs including Ofukolo, Ega, EdeAdejo, and Ede -Alaba, have been investigated for their 222 Rn concentrations using liquid scintillation counter manufactured by Packard Instrument Company. The concentration of 222 Rn in the well water samples was found to vary in the range 3.0±2.00 -18.24±1.50 Bq/L and a mean concentration of 9.64 Bq/L with An average mean concentration of 10.23 Bq/L recorded respectively. The results showed that 222 Rn concentration in well water sources were greater than the maximum concentration limit (MCL) of 11.1Bq/L set by USEPA and 10.0 Bq/L set by WHO. The annual effective dose by ingestion for adult male was found to be in the range 0.0198 mSv/y to 0.1198 mSv/yand an average of 0.0721 mSv/y which are lower than the annually received effective dose as set by ICRP.