Hamilton Water estimates that as much as 337 million litres of sanitary sewage discharged into the Hamilton Harbour over a duration of 26 years in the leak that was detected last week at Burlington and Wentworth Streets. But that is nothing compared to the amount of sewage discharge that takes place every year as a result of Hamilton having part of its wastewater system combined with the storm drains. For comparison, the city discharged more than 4 billion litres in the year 2021, nearly 12 times the amount of the recent discharge, mainly due to storm events where the combined sewage overflow tanks are overwhelmed in heavy rains. In 2020 the annual overflow events resulted in a discharge of 2.3 billion litres.
City staff developed the estimate of 337 million litres based on the water meter usage data for all of the properties connected to the combined sewer pipe. There were several ways City staff could calculate the overall estimated volume of wastewater discharged into the Hamilton Harbour, but this methodology was identified as the most accurate representation of the discharge over the time period. Staff told Public Works Committee Monday that the estimated spill is at the high end of probable scenarios.
The repair work and realignment of the sewer was completed on Wednesday, November 23, 2022 at 9:32 pm, and all sewage is now flowing into the Western Sanitary Interceptor and all appropriate repairs to the combined sewer have been completed.