Some university students in Waterloo unexpectedly have the night off due to a sewer backup. In a social media post on Thursday night, the University of Waterloo said classes scheduled for the evening were cancelled and everyone was asked to avoid all academic buildings on the main campus. The Douglas Wright Engineering building was closed. Other activities continued and student service buildings were open. “Crews continue to work on the issue this evening,” an email from the University of Waterloo, said. “Based on the information available at this time, we do not anticipate impacts to additional academic buildings tomorrow.” The school does not believe additional academic buildings will be impacted on Friday, but updates on Friday’s classes would be posted by 6 a.m.