Radioactive substance happens when there is unstable nuclei in the atom and can emit energy through high speed charged particle to become a stable state. Natural radioactivity is defined as the release of high energy radiation substance into water, air, land caused by internal, terrestrial, and cosmic radiation. If an atom becomes unstable, it will divide itself into smaller atoms. The main objective of this study is to detect both radioactivity and radio metal concentration from outlet water using a high purity germanium detector with the help of gamma accusation software. rnThe sample water, taken from the outlet zone, detected by high purity germanium detector, using 70 litter of liquid nitrogen with the help of gene2000 software,is the crucial research work to measure the natural radionuclide contamination of U-238, Th-232, and K-40. The activity concentration for radionuclide elements in the first water samples are listed: k-40 is found to be 1.0241E+002Bq/l, U â€“ 238 is about 2.5971E +000Bq/l, and Th -232 got 8.53835E +000Bq/l. The activity concentration in the second water sample for k-40 is 9.7944E+001Bq/l. Th-232, one of the radionuclide elements has been found to be 9.134E+000Bq/l. Likewise, U-238 is found to be 3.0704E+000. In the third sample, k-40 is found to be 9.5874E+001Bq/l, U-238 become 2.5706E+000Bq/l, and TH-232 got 7.9461E+000 Bq/l . rnLastly, In the 4th sample, the activity concentration for k-40 becomes 4.330E +000Bq/l. This result shows the activity concentrations of U, TH, K are within the limit value, so the outlet water is safe from this pollutant.