e. coli levels on the lake

About E. Coli: swimming hazards, testing and prevention.

What is E. Coli?
Escherichia coli (E. coli) is a type of bacteria (single cell organism) that is used by the State of Michigan as a water quality indicator. When E. coli is found in surface waters, it means that there has been fecal contamination. While E. coli itself may be harmful to human health, other disease causing organisms might also be present. Watch this short video to learn more about E. Coli.

Why is E. Coli dangerous to swimmers?
Once these pathogens are in a stream or lake they can infect humans through ingestion or skin contact, resulting in diseases such as gastroenteritis (diarrhea), giardia, hepatitis, or cholera.

Note that all lake and river water has some level of E. Coli present! What is important is that E. Coli levels remain below 300 E. Coli per 100ml of water for a single sample and 130 E. Coli per 100 ml over a month. In 2023, on Lake Fenton we recorded between 0 and 31 E. Coli per 100ml for the entire year. See the latest test results here.

How does E. coli get into surface water?
Common and potential sources of E. coli contamination vary by where you are in the landscape.  For example, urban areas would be expected to have a different set of sources than a rural farm-type setting where there are livestock and people rely on septic systems. All animals (like domestic pets and wildlife like birds on the lake) and human sewage are possible sources under certain circumstances.

How do we test for E. coli?
Volunteers take water samples weekly at the Fenton Township Hall swimming beach. These samples are sent to a lab and the data is posted. If e. Coli levels are too high (it last happened in 2010) the beach will be closed. See the latest test results here.

Water Quality Standard for E. coli
The Water Quality Standard for E. coli was developed to protect human health during work and play, and is the maximum amount of E. coli that is allowable in surface waters in Michigan:

Total Body Contact (May 1 - October 31):

• Daily Maximum Geometric Mean: 300 E. coli per 100 milliliters (ml)
• 30-Day Geometric Mean: 130 E. coli per 100 ml

Partial Body Contact (all year):

• Daily Maximum Geometric Mean: 1,000 E. coli per 100 ml

What can lakefront homeowners do to help?

• Clean up pet waste in your yard and dispose of it in the trash or by composting.
• Do not feed wildlife, including geese and seagulls at parks and beaches.
• If you own a pet with an outdoor run, pasture, or kennel (dogs, chickens, horses, etc.) keep a well-vegetated buffer between the pet area and nearby surface waters.
• Discourage raccoons by keeping trash in proper storage and shoring up outbuildings.
• If you own a horse or other large pet that requires manure storage: store in a flat area as far away from surface water as you can manage. Ideally, the waste would be covered to keep rain off (a tarp works)