If the Water’s Green – It’s not Clean – Keep your dog away.

It’s that time of year again, late summer, when the weather’s hot, the water’s stagnant, and bright green scum floats on the surface of the lake.   Take a scoop of the lake water with a clear cup. Are there green particles suspended in it? Does it look like someone dumped green paint on the lake? Likely, it’s blue-green algae or cyanobacteria–even though the water looks green.

My last springer spaniel would jump in any body of water, lie down and take a drink. But don’t let your dog do this. Many dogs each year get very sick and some die. Just today, I read an article about a dog dying from drinking algae infested water. http://www.nottinghampost.com/Heartbroken-angler-warns-dog-owners-war-blue/story-27700021-detail/story.html

Blue – green algae toxins affect dogs, people, and other animals. Last year Toledo shut down its water distribution because blue-green algae toxins on Lake Erie entered in its water supply. It may happen again this year. http://www.usatoday.com/story/news/nation/2015/07/30/another-toxic-algae-outbreak-feared-lake-erie/30916703/

Toxins are not always present when the lake looks this green, but be on the safe side and stay away. Not all species of blue-green algae form toxins, and of the species that do, they do not always produce toxins. Various tests can determine if the toxins are present. But the water conditions can change rapidly. If the cells die, they release their toxins into the water. The various types of toxins can affect the liver, nervous system, or the skin.

Symptoms of algae toxicity

Blue-green algae scum on a lake.
Blue-green algae scum on a lake.
  • abdominal cramps
  • nausea
  • diarrhea,
  • vomiting
  • fever
  • seizures
  • headache
  • muscle and joint pain
  • blisters of the mouth or skin rashes

If any of these symptoms occur, take your dog to the vet immediately (or yourself to the ER). Most dogs die within days or even hours after drinking contaminated water.


  • Install signs warning of the blue-green algae hazard.
  • Prevent dogs from drinking and swimming in blue-green algae.
  • Don’t swim in areas with blue-green algae blooms.

Long-term prevention involves reducing nutrient loading into the lake, which would eventually limit algae blooms, but it may take many years to see an effect.