An evaluation of the efficiency of conventional clariflocculator units with tube settlers has been done in this study within the compact units in Mosul Unified Water Project. Results of bimonthly samples were analyzed before and after treatment in the conventional project with their correspondences in tube settlers within the compact units during period of January 2003 to June 2004 in order to investigate the expected water quality variety in Tigris river. The results have shown that tube settlers are more efficient than conventional clariflocculator units in removing turbidity and phytoplankton alga at a low turbidity level less than (30 NTU) and number of phytoplankton alga between (45–59) cell/ml. )75%) of the residual turbidity and phytoplankton alga after treatment was the best in tube settlers units. Results also showed that conventional clariflocculator units are more efficient than tube settlers at the water turbidity more than(30 NTU) and number of phytoplankton alga between (63–75) cell/ml. (25%) of the total residual turbidity and phytoplankton alga after treatment was the best in the conventional clariflocculator units.