Boil Water Advisories

The municipal systems that serve 80% of Alberta’s population with water are regulated by Alberta Environment and Sustainable Resource Development (AESRD). AESRD receives and collects reports and data summarizing the results of drinking water quality testing. The physical, microbiological, chemical, and radiological characteristics of portable water are analyzed according to Potable Water Regulation. If the results do not meet the Maximum Acceptable Concentration or Interim Acceptable Concentration specified in the Guidelines for Canada Drinking Water Quality, then Alberta Environment alerts Alberta Health Services (AHS)[1].

Boil Water Advisory Definition

In Canada, ‘The Guidelines for Canadian Drinking Water Quality’ are established by the Federal-Provincial-Territorial Committee on Drinking Water and subsequently published by Health Canada[2] but boil water advisories are issued at the provincial/territorial or local level. Depending on the jurisdiction, the term ‘boil water order’ and ‘boil water notice’ may be used instead of, or in conjunction, with the term ‘boil water advisory’.

Boil water advisories are issued either as a precaution or in response to a waterborne disease. For example, precautionary boil water advisory may be issued when local emergency repairs in the distribution system are needed.

Additionally, a boil water order is often issued in response to evidence indicating that drinking water is or may be responsible for an outbreak of illness[3]. Boil water orders are issued when microbes like E.coli bacteria or Giardia parasites may be present in drinking water[4]. Boil water advisories may also be issued in response to unacceptable levels in the cloudiness (turbidity) in the water at its originating source[5].

During a boil water advisory/order the public is advised to boil tap water used for drinking, preparing food, beverages, ices cubes, washing fruits or vegetables, or brushing teeth[6].

High Streamflow and Flooding’s Impact on Water

Under normal spring conditions, maintaining water quality during is more difficult task for water treatment facilities. In the spring decaying organic matter makes its way into rivers and increased stream flows churn up mud and silt making the water cloudy.

During a flood water treatment becomes even more difficult. If a water treatment plant is not overloaded, physically damaged or inundated with flood waters, facilities can often treat highly turbid flood waters[7]. However, in the days following the 2013 Flood, peak river flows were about four times higher than during the flood in 2005[8] leaving many water treatment facilities inundated by floodwaters and resulted in boil water advisories and orders across southern Alberta.

[1] Alberta Health Services. (September 26, 2013). Backgrounder: Water Quality Regulations (Alberta). Retrieved from 

[2] Health Canada. (August 2012). Guidelines for Canadian Drinking Water Quality-Summary Table. Retrieved from 

[3] Health Canada. (2008). Environmental and Workplace Health: Boil Water Advisories and Boil Water Orders.

[4] Alberta Health Services. (nd). What to Do During and After a Boil Water Order. Alberta Health Services.


[6] Health Canada. (2008). Environmental and Workplace Health: Boil Water Advisories and Boil Water Orders.


[8] Halfride. R. (2009). City of Calgary Water Services. Business Excellence Magazine.