This section shall apply to all proposed new developments or redevelopment (with an SEP or site utility plan) that increase base sanitary flow from the site connecting into or upstream of any CIP-size trunk sewer stretches or any wastewater pumping stations that have projected overflows based on existing dry weather flow (including groundwater infiltration) and rainfall dependent infiltration and inflow from a two-year design storm specified by WSSC. The applicants for such developments shall be required, as a condition for service, to obtain a release for service (RFS) from WSSC for the sewer system improvements needed to eliminate excessive surcharging, as determined by WSSC, under the two-year storm after addition of the proposed base sanitary flow from the development under review. Consideration and evaluation of alternate solutions including construction of new sewer lines and facilities and/or rehabilitation/reconstruction of existing sewer mains, appurtenances, and facilities may be required. Any new sewers or facilities built shall be sized to handle projected future base sanitary flow and the infiltration and inflow from the 10-year design storm.

In addition, the development will be evaluated for the potential impact of any projected surcharging and, in particular, the potential for causing backups into homes or businesses. Any surcharging in a sewer segment that contains service connections in which the hydraulic grade within the sewer is higher than the basement floor elevation (for structures with basements) or first floor elevation (for structures without basements) is prohibited as the condition will potentially cause sewage backups into the structures. The applicants for such developments shall be required, as a condition for service, to obtain a release for service (RFS) from WSSC for the sewer system improvements that eliminate backups under the two-year storm after addition of the proposed base sanitary flow from the development under review. (REG-IFSM-EC-2016-007)