Edmonton - A water main break caused a backflow incident within a facility from the fire protection system
(brackish water). A single check valve failed on the fire system in the high-rise building. A booster pump that supplies water to the upper floors kicked in and provided the water to the upper floors, but while the break was in effect the booster pump did not provide water to the upper floors. The brackish water from the fire standpipe system did not enter the City water main, but was pumped into the building. Fortunately, no residents were reported sick.

Edmonton - Plumbing repairs were performed in a high-rise apartment, where the valve at the meter was shut off.  During the repairs a tenant on one of the lower floors opened the tap to let the cold water run from
the tap. Later blue (caustic) water was coming from the tap and had drained caustic chemicals from
a heating system into the building's potable water lines. Fortunately no one was injured from the incident, however, the caustic/contaminated water took 1-2 weeks to flush from the lines as it appeared that during the backflow incident, the caustic embedded itself into the calcium and magnesium deposits in the line and was difficult to remove.