Washington Suburban Sanitary Commission (WSSC) Development Services Group reviews hydraulic plans for approximately 160 proposed development plans per year. This includes water and sewer system extensions as well as approximately 172 small-site utility plans (commercial private systems) that connect to the existing water and sewer network in two large Maryland counties.
Each system extension is hydraulically reviewed and mains are properly sized by WSSC hydraulic engineers during the hydraulic plan analysis (HPA) process. In this process, engineers use hydraulic-grade benchmarks developed by the planning group within the existing system to analyze the proposed extensions and connections. These benchmarks are developed using system-wide modeling while considering the severest conditions in the system.