The quality of the water in Lake Huron has been a concern for Bluewater shoreline residents for several years. We ask ourselves: Is the lake safe for swimming? What is the pollution level in the lake? Should my children/grandchildren play in the ravine water? What factors play a role in contaminating the lake water? Are there remedies for this contamination in the lake? With persistence, the Bluewater Shoreline Residents’ Association (BSRA) has worked, and continues to work, to find answers to these questions.

BSRA’s long term goal with respect to water quality is to see the lake meet the pre 2018 provincial water quality standard (<100 E. coli cfu per 100 mL of water, the province changed its threshold to 200 cfu) 100% of the time. In the shorter term BSRA’s goal is to bring about a reduction in the percentage of time that ravine and lake water exceed the provincial standard.

Beginning in 2006, BSRA began a cooperative program with the Municipality of Bluewater and the Ausable Bayfield Conservation Authority (ABCA) to test water quality in four Bluewater ravines and the lake water at the mouth of these ravines. Sampling for Escherichia coli has been carried out weekly from mid-June to the end of August and has conformed to the water testing protocol mandated by Ontario’s Ministry of Health. The four ravine and beach testing sites have been: Wildwood, Houston Heights, St. Joseph and Ridgeway.

The ABCA Reports on the annual test results can be found in the Water Quality Library on this website.  The weekly results for the current year are posted under Water Quality Test Results.

Is the lake safe for swimming? The short answer is sometimes.

When summarized, the results for water quality along Bluewater’s Lake Huron shoreline are not encouraging. For example, in 2012, 49% of the water samples taken at Wildwood exceeded the provincial water quality standard for swimming. At Houston Heights, 54% of the samples exceeded the standard. For St. Joseph and Ridgeway the results were 37% and 32% respectively. This is not good news.

How do I determine if it is safe to swim?  According to the Huron County Health Unit, it is safe to swim if you can see your feet when you are standing knee-deep in the water.  When the lake is rough and bottom sediment becomes stirred up, the concentration of E.coli generally rises to an unacceptable level.

Should children play in the ravine water?  In a word – NO!  Testing shows that the water in the ravines is always contaminated.  Your dog shouldn’t be in that water either.

What is the source of the Escherichia coli pollution in the lake? There are several ways in which E. coli enters the lake and recent research has helped to clarify this issue.  In 2009 the University of Guelph published the results of its DNA analysis ofE.coli in the Eighteen Mile River Watershed. This watershed is typical of many beach/ravine areas along the Lake Huron shoreline – a sand/gravel beach area backed by clay cliffs – with cottages along a narrow strip at the top of the bluff and agricultural land sloping eastward from the bluff.

By analysing DNA in the E. coli found in water samples, these researchers determined that the sources of the E. coli were: 59-62% livestock manure runoff, 16-18% environmentally adapted strains of E. coli in the swash zone, 5-14 % wildlife and 2-3 % human.

This research paper can be found at this link on

What is the “swash zone”? The linear strip along the shoreline where waves run up onto the sand is referred to as the “swash zone” – that part of the beach where children love to play. This continually-damp sandy area is also an area where E. coli is located. So far, no studies have suggested that there are health risks associated with children playing in this sandy area. However, parents are wise to finish up a day of play on the beach with a cleanup using hot, clean, soapy water.

Why are there algae blooms appearing along the shoreline? Green algae growth proliferates when there are excessive nutrients like nitrates and phosphates in the lake water. These nutrients are primary components in fertilizer products and reach the lake when there are heavy rains and runoff from agricultural land and residential properties. Faulty septic systems along the lake also contribute to this problem. Property owners along the shoreline can help reduce the nutrient loading in the lake by reducing and/or eliminating the use of fertilizers on their lawns and gardens, eliminating runoff of soil from construction or landscaping activities and ensuring that their septic system is functioning properly.

Is anyone doing anything about this problem? A coordinated approach to finding answers and solutions to contamination in Lake Huron – led by the Lake Huron Southeast Shoreline Working Group – is finally underway. Read about the research work and studies being carried out to develop workable ways to reduce lake pollution at Healthy Lake Huron

Other websites that are related to water quality issues in Lake Huron include the following:

Ashfield Colborne Lakefront Association:

Ausable Bayfield Conservation Authority:

Bayfield Ratepayers’ Association:

Huron County Health Unit:

Lake Huron Centre For Coastal Conservation: