Getting sick from swimming should be the last thing on your mind when you head to the beach for a day of fun.

However, getting a waterborne illness from swimming in contaminated waters is all too common. Although you’re actually more likely to get sick from swimming in a pool than a beach, you can still get sick from rivers, swimming holes, ponds, lakes, oceans, and other wild waters.


1. What causes contamination in natural waterbodies?

Your local waters can become contaminated for a number of reasons. They can be contaminated by combined sewer overflows, runoff, blue-green algae blooms, plastic pollution, and more.

Contaminants such as bacteria, parasites, viruses, chemicals, pathogens, pollutants from sewage, human and animal faeces, urban or agricultural runoff, and other pollution can all end up in natural waterbodies.


2. What are recreational water illnesses?

Recreational water illnesses occur when you come into contact with contaminated water. Recreational water illnesses can lead to gastrointestinal infections, eye, ear, and nose infections, rashes, or respiratory illnesses.

Enteric illness is the most frequent outcome of recreating in contaminated water. Enteric illness causes nausea, vomiting, abdominal pain, and diarrhea. More rare (but serious) outcomes from coming in contact with heavily polluted waters include typhoid fever, hepatitis, gastroenteritis, and dysentery.


3. How can you be exposed to recreational water illnesses?

You can get sick with a waterborne illness in a number of ways:

  • By inhaling contaminated water
  • By swallowing contaminated water
  • By skin contact with contaminated water
  • Through openings in your body (like eyes, ears, nose, or cuts)
  • Certain water activities put you at a higher risk of illness or infection that others. The more contact you have with contaminated water, the greater your risk of getting sick.

    Photo by Meghan Callon

    Primary contact activities (like swimming, surfing, or water skiing) are high risk, though you can still become sick from secondary contact activities (like fishing or sailing).


    4. How common are waterborne illnesses?

    If you swim in a natural waterbody, you have an estimated 3%-8% average chance of getting sick. Every year, an estimated 3.5 million Americans and 400,000 Canadians get sick from swimming in contaminated water.

    When are you most at risk of contracting a waterborne illness?

    • After rainfall, contaminants are washed into the water and combined sewer systems can overflow. Protect your health with the 48-hour rule (do not enter the water until 48 hours after a rain event).
    • During the busy summer season, crowds of people bring contaminants (like fecal waste and microbes) into the water. Always shower before and after swimming.
    • At beaches with poor water quality posted, such as high bacteria or algae blooms, do not use the water.
    • Near sewer outfalls, water treatment plants, and rivers mouths, there are likely higher levels of contamination in the water, so swimming in these locations is riskier.

    Children, pregnant women, the elderly, and people with weakened immune systems are most at risk of waterborne illnesses. Higher concentrations of contaminants in the water and more extensive contact with the water increase your risk of contracting a waterborne illness.


    5. How Swim Guide protects you from waterborne illnesses

    Recreational water quality standards were established to protect people from waterborne illnesses. These standards determine how much of a contaminant can be in the water before it becomes an unacceptable risk to people or the environment.

    Like the weather, water quality changes all the time. That’s why sampling and testing water is such a crucial part of protecting human health.

    Swim Guide keeps you safe by using recreational water quality standards to answer the question, “Where can I go swimming?”

    Swim Guide lets you know where and when the water is contaminated or clean to help you make an informed decision about whether or not to go swimming. With so many inviting and pristine beaches to swim at, you don’t need to settle for getting sick. With Swim Guide, you can find the cleanest, best local beaches so that you can swim without worry.

    The bottom line? No one should get sick from enjoying their local waters.

    Checking water quality information on Swim Guide is the best way to prevent waterborne illnesses. Visit your favourite beach on Swim Guide to learn your local water quality standards, what your waters are tested for, and more about the watershed that you live in.

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