Dalhousie University's campus in Truro, N.S. is under a boil-water order after a test conducted late Wednesday afternoon came back with trace amounts of coliform bacteria, according to a university spokesperson.

Drinking water is now being delivered to all campus buildings, including residences with approximately 350 students, the dining hall and the library.

"This has not happened in the past five years but has previously," Stephanie Rogers, a spokesperson for Dal, wrote in an email. "Therefore we have procedures in place that we have now implemented."

Rogers said two tests done 24 hours apart must show there is no more coliform bacteria in the water before the university will lift the boil order.

It could be early next week before the results of those tests come back, she said. The water system's lines are also being flushed with chlorine to kill the bacteria. 

Water will continue to be delivered to the campus until people can safely drink tap water again. 

If the test detects the bacteria again, Rogers said the campus has a treatment plan "to help us resume normal activities as soon as possible."

Because coliform bateria can make people sick, the university has posted signs around campus advising students to boil water for two minutes before drinking, making ice cubes, washing food and brushing teeth.