An investigation into a leak that’s been spilling Hamilton sewage into Lake Ontario for 26 years revealed that another pipe has also been dumping waste into the water for the same amount of time.

The newly-discovered leak was uncovered on Saturday at Rutherford and Myrtle avenues, city officials said in a news release on Monday.

The city says the root of the leak dates back 26 years.

As many as 11 residential properties have been flushing sanitary wastewater into Hamilton Harbour since 1996. That year, a newly constructed storm sewer was connected to a 100-year-old combined sewer pipe, according to a preliminary investigation.

Since then, the wastewater has been spilling into a storm sewer leading into the harbour.

At this point in time, the city says it’s unclear how much waste was discharged, but the exact volume will be publicly reported when the assessment is complete.

This inspection was triggered by a similar discovery on Nov. 22. A leak, caused by a hole in a combined sewage pipe, was uncovered. Meaning, 50 or so Hamilton residents had been flushing sewage into the Hamilton Harbour for 26 years.

Over that time period, as much as 337 million litres of waste was released into the harbour and repairs are expected to cost $29,830.

In the meantime, while determining a “permanent remedy” for the spill discovered on Saturday, the city says a vacuum truck has been mobilized to stop further discharge into the harbour.

The recent spills follow a 24-billion-litre sewage leak in Cherdoke Creek in 2018. Remediation efforts are ongoing.

With files from CTV News Toronto's Abby O'Brien.