Some students living at McMaster University’s Bay Street residence will need to temporarily move-out once again as crews continue to work to flush out bacteria on a number of floors.

In an update issued on Thursday, the university said that around 23 students on three floors of the building at 10 Bay St. will be affected by the temporary relocation.

This follows another planned move-out period at the beginning of the month.

The building’s 200 residents left to clear the way for the school’s latest attempt to flush bacteria out of the water supply, with students saying beforehand that they hoped it would be the end of the issues.

Previous chlorination efforts focused only on the building’s main water pipe, which is less disruptive. This time, the complete system was fully flushed.

READ MORE: Bacteria still present at McMaster residence water after planned evacuation

Following that chlorination process, McMaster reported that total coliform bacteria is still being found in 5 out of 58 water samples taken by their consultants after the staged move-out.

The negative results are all contained to a single building zone, inclusive of floors 10 to 16, while all other floors came back as clear.

Those residents living on the affected floors will be forced to leave once again from Feb. 20 to 25.

Crews are expected to focus on chlorinating the water system on floors 10 to 16 beginning next Tuesday.

According to McMaster, the affected water supply is contained to a single plumbing zone, meaning it cannot contaminate water on the floors above or below it.

WATCH MORE: Residents at downtown McMaster residence forced to evacuate

At this time, over 17 floors in the 30 storey building continue to be clear of any bacteria.

In an email to residents last Friday, the school said it remains committed to resolving the issue as soon as possible and will offer 100 per cent, total rent reduction for the month of February.

In addition, residents will continue to be supplied water until all bacteria is cleared from the system.

Students living in the building are expected to receive another update from school officials on Wednesday.