Based on a pilot test of sludge water reuse in the sedimentation tank of the water treatment plant, the water quality safety and biological stability characteristics of the effluent from the sludge reuse process and the feasibility of the sludge water reuse in the water treatment plant were discussed. The results showed that the average concentrations of AOC and BDOC in sludge water were 98.16 μg/L and 1.92 mg/L, respectively. The concentration of AOC and BDOC was significantly correlated with water temperature. The total number of bacteria in effluent water was not detected, and the turbidity, ammonia nitrogen, CODMn and other indicators of water all conform to Sanitary Standard for Drinking Water Quality (GB 5749-2006) when the sludge return ratio (sludge: raw water) was 3%. The average concentrations of AOC and BDOC in the effluent were 88.67 μg/L and 0.21 mg/L, respectively, which guarantee the biostability of the water. Therefore, the recovery of sludge water under the condition of reasonable control of return ratio is not only implementable, but also realizes the sustainable development concept of energy saving and emission reduction of the water treatment plant.