This research is accomplished to the soften of groundwater at Tikrit University site by using reverse osmosis (RO) membrane system. RO type TW 30 -1812- 50 is used in this research. The system achieved water recovery rate percentage between 6.75% - 7.75% and salt rejection percentage ranged between 89.22% - 92.2%. Also the results showed high removal efficiency for physical and chemical concentrations of raw groundwater for TDS (89.22 - 92.2 %, EC (88.0 - 91.29)%, Turbidity (53.65 - 81.25)%. Total Hardness (94.11- 95.55 %, Alkalinity (96.25 - 97.00) %, Ca (92.88 - 96.43) %, Mg (91.95 - 96.52)%, Cl (93.68 - 94.27)%, SO4 (85.66 - 90.37)%, Na (75.72 - 96.36)%, and Fe 100%. ROSA 72 software program is used in designing of reverse osmosis then the results were satisfied and accepted.