Well there is a reason. The City of Winnipeg has reported that Algae plants have been growing in Shoal Lake. Shoal Lake, is Winnipeg’s prime water source. The growth of Algae effects the water by either giving it a musty smell or takes away the clarity of the water.
Winnipeg health officials say that the water is safe to consume. I say stick to the bottled stuff ;) (Don’t forget to recycle the bottle)
For a more “clearer” explanation visit Winnipeg’s Water and Waste Website.