:A discharge to the environment from a combined Sewer system that occurs because of a precipitation event when the capacity of the interceptor sewer or treatment plant is exceeded. It consists of a mixture of sanitary wastewater and Stormwater runoff. | :A discharge to the environment from a combined Sewer system that occurs because of a precipitation event when the capacity of the interceptor sewer or treatment plant is exceeded. It consists of a mixture of sanitary wastewater and Stormwater runoff. |