The pipeline flexible device is suitable for environments with temperatures ranging from -30°C to 50°C, and for raw water, rainwater, or sewage with medium temperatures from 0°C to 40°C. The pipeline flexible device system, controlled pneumatically, achieves pollution separation. This facility can divert dirty water from the residential area to the municipal sewage pipe for treatment in the sewage treatment plant or store it in a regulating reservoir. Cleaner rainwater from the residential area can be discharged into the municipal rainwater pipe or nearby natural water bodies. This system is suitable for the renovation of older residential areas.