The effective inactivation of microorganisms in drinking water by Ultraviolet (UV) irradiation is regarded as a new low-cost water treatment method shoeing high removal rate of relatively stable infectious virus particles including poliovirus. In the present study, we examined virus inactivation by UV in various water environments. Samples were collected from finished water and surface water, and tested for turbidity. UV dose of 18, 22, 30, 36 and 40 milli-Joule $(mJ)/cm^2$ were used by combination of $2;mW/cm^2$ UV intensity and time of 9, 11, 15, 18 and 20 second. Depths of water were fixed at 0.37 cm and 8 cm, and virus titers were shown by plaque forming unit (PFU). Poliovirus was inactivated to 99.0% by $18;mJ/cm^2$ of UV dose in the condition of 0.08 Nephelometry Turbidity Unit (NTU) and 8 cm depth of water. Poliovirus at $30;mJ/cm^2$ of UV dose under the same condition was inactivated to 99.7%. Furthermore, Poliovirus at 56.60 NTU and 8 cm depth of water was inactivated to 92.0% and 98.5% by $18;mJ/cm^2$ and $30;mJ/cm^2$ of UV dose, respectively. The degrees of virus inactivation were dependent upon the UV dose, the turbidit, y and the depth of water. In conclusion, introduction of UV disinfections can be considered in drinking water purification systems in case reasonable engineering support is possible.