discharge of sewage when the flow capacity of a sanitary sewer system is exceeded.

a discharge of raw sewage from a municipal sanitary sewer system

A discharge of raw domestic sewage from a separate sewer system before the headworks of a wastewater treatment facility.

The overflow of a sanitary sewer into a river or stream

Discharge of untreated sewage directly to streams and the bay from wastewater collection systems typically due to heavy rainfall events where the capacity of the system is exceeded or due system malfunctions.

Sanitary sewer overflow (SSO) is a condition whereby untreated sewage is discharged into the environment, escaping wastewater treatment. This situation, also known as Wet Weather Overflow, is primarily meaningful in developed countries, which have extensive sewage treatment facilities.