Dogs Are Dying in Water Across America – and Here’s Why

August 26, 2019 by Douglas A. McIntyre

The State of New Jersey recently warned people not to swim in Lake Hopatcong, the state’s largest lake. In fact, people have been told not to touch it. Large parts of Lake Erie, one of the biggest freshwater lakes in the world, are unsafe for dogs to swim in. Similar warnings have gone up in lakes across the United States over the course of the summer.

While the danger to humans is real, dogs across the country have succumbed after swimming in toxic water. A woman lost her three dogs in Wilmington, North Carolina, earlier this month. Another dog died in a wading pool in Texas. While these are just anecdotes, signs and public warnings about dogs swimming in or drinking toxic water have gone up around the United States. One reason, according to Larry Brand, a University of Miami marine biology and ecology professor, “Although they can also be deadly for humans, dogs are far more likely to ingest them.”

Some cities and states have put out official warnings about lake algae danger to dogs. Among the most recent are in Illinois and Massachusetts.

Water in the lakes has become dangerous for several reasons. The primary one is chemical runoff. For example, industrial fertilizer and animal manure have polluted much of Lake Erie, causing rapid growth of blue-green algae that in turn robs the water of oxygen. Wide areas that are affected are called harmful algal blooms. The National Oceanic and Atmospheric Administration (NOAA) reports the existence of harmful algal blooms exist in every coastal state. The number of factory farms is increasing rapidly, and many are not regulated.

An area in Lake Erie making up thousands of square miles is called “the dead zone.” It is filled with oxygen-absorbing algae, fed by fertilizer used mostly for farming. The water the lake supplies may not be potable, as some fish die, adding to the toxic stew. These are some major cities where the drinking water may soon become toxic.

The problems are not isolated to dogs. People who come into contact with toxic lake water, either by accident or poor judgment, can face extremely severe health consequences. Among these are flu-like symptoms, gastroenteritis, respiratory irritation, skin rashes and eye irritation. Some of the reactions can be much worse and cause hospitalization. The Centers for Disease Control and Prevention (CDC) indicates that these recreational water illnesses are caused by germs spread by swallowing or coming in contact with contaminated water, which can even spread to the sand on beaches. The most common symptom from these is diarrhea.

The CDC has several rules about how people can prevent toxic lake and river water illnesses. Virtually all apply to dogs as well.

  • Look for algae blooms in the water. They usually appear as large masses that look like foam or scum. They can be blue, green, brown, yellow, orange or red. They often smell like rotting plants.
  • Don’t eat fish from lake water that has algae blooms.
  • Check for information about lake water quality posted at by local or state governments.
  • If you enter a lake with algae blooms, wash yourself off immediately with tap water.
  • Stay out of sand or dirt around infected lakes.

Help others by reporting toxic water to the Phytoplankton Monitoring Network.

A year ago, a number of people went to emergency rooms because they came in contact with blue-green algae in the St. Lucie River. In extremely severe cases, people suffer liver damage or can be hospitalized for extended periods. Some infections are more worrisome than others because they are caused by bacteria that have become resistant due to overuse of antibiotics. These are infections even doctors are afraid of.