Seasonal algae growth starting to affect Winnipeg's tap water

WINNIPEG - July 09, 2004 - “As a result of algae growth in Winnipeg’s water supply, some residents are noticing an unusual taste and odour in their tap water,” says Diane Sacher, Manager of the City’s Water Services. “This is a condition we can experience each year. The proposed water treatment plant, which is scheduled to be operating by the end of 2007, will reduce odour levels in tap water, as well as improve the overall quality of Winnipeg water”, says Sacher.

Algae are plants that live in bodies of water, including Shoal Lake, Winnipeg’s water source. When conditions are favourable, usually in the summer, the algae can grow in abundance, in what is called an ‘algae bloom’. Algae produce substances that can give our water an unpleasant taste and smell, often described as musty. Algae could be a factor until late fall.

Dr. Margaret Fast, Medical Officer of Health with the Winnipeg Regional Health Authority says, “These tastes and odours may be unpleasant, but algae normally found in Winnipeg’s water supply are not known to cause adverse health effects. Residents can continue to use the water, and there is no need to take special precautions.”

Winnipeg water is routinely tested during the summer season for substances produced by algae. Included are tests for microcystin-LR, which can pose a health concern at high levels. Microcystin-LR has never been detected at levels that would cause concern, and is normally not detected at all. This year, monitoring for microcystin-LR started in early May, and the substance has not been detected so far. The monitoring program will continue until late fall.

Increased algae growth can also cause home water treatment devices and water tap strainers and aerators to plug more frequently. A build-up of sediment may also occur in hot water tanks. Residents are encouraged to perform regular maintenance on these devices to ensure that they continue to function satisfactorily.

Water filters and other home water treatment devices with this certification on their label can improve the taste and odour of tap water: ANSI/NSF Standard No. 42 for the reduction of taste and odour.

For more information on Winnipeg’s water, residents can:

• Visit our Web site at winnipeg.ca/waterandwaste/water
• See the two blue pages at the back of the MTS White Pages Phone Book
• Call the Water and Waste Department Customer Service Centre at 311