As if coping with a flood warning near the overflowing Charles River and addressing elevated PFAS6 levels in its drinking water supplies through a mandatory water ban for nonessential use isn’t enough for Natick.
The town has also passed along a state warning to residents of toxic algae bloom at Lake Cochituate and is spreading the word that E. coli bacteria has been detected at its Elm Bank wells.
The Massachusetts Department of Conservation and Recreation (DCR) has warned the public not to swim in Lake Cochituate due to the presence of cyanobacteria (blue-green algae bloom) throughout the 635 acre body of water located off of Route 9 and Route 30 in the towns of Natick, Wayland, and Framingham.

Boating and wading are out, too, and pets should be kept away from the popular recreation area. The CDC says that cynobacterial blooms can be deadly for pets. Animals can get very sick and die within hours to days after swallowing cynobacterial toxins. Toxicity of the blooms cannot be determined just by looking at them.
Signs have been posted to warn individuals against contact with the water.
Avoid the following at Lake Cochituate:
- Do not swim
- Do not swallow water
- Keep pets away
- If exposed to the water, people are advised to rinse off after contact. Pets should also be rinsed off if exposed as well.
The Massachusetts Department of Public Health will conduct follow-up sampling at the waterbody when there is no longer visual evidence of a bloom.
For more information, please check the MA DPH website page on Harmful Algal Blooms in Freshwater Bodies at: www.mass.gov/info-details/harmful-algae-blooms-in-freshwater-bodies
You may also call the Bureau of Environmental Health Toxicology Program at (617) 624-5757 or the Natick Board of Health at (508) 647-6460 with any questions.
E. coli detected
Natick’s Water/Sewer Division issued a drinking water notice (embedded below) to the public that stresses there’s no need to boil or avoid drinking the water. Acting Town Administrator Jamie Errickson gave a heads up about this news at Wednesday’s Select Board meeting about 9 minutes into the Natick Pegasus recording.
This after discovering a sample of untreated water taken at the Elm Bank Wells on July 13 tested positive for E. coli, which yecch, is a fecal indicator. (We blame the ubiquitous Canada Geese, which we blame for everything.)
Natick has turned off the Elm Bank wells, which have been increasingly relied on during the town’s efforts to mitigate elevated levels of PFAS6, aka forever chemicals that were detected earlier this year. Natick recently approved spending $3M to install carbon filters to get rid of the unwanted chemicals, which through longtime exposure can cause health issues.
Natick disinfects the water it distributes to remove any fecal matter contaminants. The town is conducting more testing to make sure it isn’t letting anything sickening through to residents. It is also attempting to get its disinfection system certified by the state.
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