~ Water Testing on McGregor Lake ~

For almost 20 years, we have been testing surface water conditions once or twice a season for Escherichia coli bacteria. Commonly called E. coli, this is one of the most common species of coliform bacteria. It is a normal component of the large intestines in humans and other warm-blooded animals. It is found in human sewage in high numbers. E. coli is used as an indicator organism because it is easily cultured, and its presence in water in defined amounts indicates that sewage may be present. If sewage is present in water, other disease-causing bacteria may also be present.

It is important to note that given the many factors and variables, results from one sample testing to another can vary significantly even at the same time in the same general location. As such, these tests help us to monitor any changes or trends in the level of contaminants in the water over time. So far, and including this recent round of testing, our levels remain fairly good, and stable. However, some long time readers might notice that some levels in typical trouble spots are higher this year. This is likely due to the extended hot weather and increased algae and plant growth in the water.

So what causes higher levels and what does it mean? Heavy rain, spills, leaking septic systems and runoff from shorelines as well as bird and animal droppings are the most common factors that can affect bacteria levels. Acceptable levels for swimming and recreational activity are counts ≤ 200 E.coli per 100 mL of water. When higher levels are indicated, you could be exposed to bacteria that may cause diarrhea or infections in your ears, nose, throat, eyes or skin.

We do not test for drinking water standards which must be free of any trace of E. coli. Since all recreational waters are likely to contain some E. coli, it is generally advised not to drink any lake water without an appropriate water treatment process in place.

We test each year, in summer, and are always looking for volunteers to help with the sampling. It is a great way to get your kids more involved in water stewardship at the cottage! It will require less than an hour of your time and you’ll need to gather and return 5 to 6 samples to us. To participate, please send us an email at lacmcgregorlake@gmail.com.

Author: Debbie Morrison

(Note: Results of the Federation of Lakes 2015 Water Quality Survey are posted below the maps at the bottom of this page.)

Results of Water Testing

May 2019

July 2018

July 2017September 2015

July 2015

June 2014


Federation of Lakes Survey of Waterfront owners of Val-des-Monts

In 2015, volunteers from 23 lake areas in Val-des-Monts took part in the État de vieillissement des lacs project. The goal was to gather water samples to register each lake’s phosphorous, dissolved-organic-carbon and chlorophyll levels three times over the summer (mid-June, mid-July, and mid-August). In addition, the volunteers evaluated the water transparency at each sampling. The overall results of the survey, which will help determine the trophic status or “age” of each lake, as well as which lakes need added care, are posted on the Federation of lakes website – Water Quality section. The report on McGregor Lake is available here (available in French only).