Is Swimming in a Lake Safe?

You’re staring out at the bright sun’s reflection on the calm, shimmery water. The peaceful sounds of nature emanate along the shoreline. It’s the perfect moment for a refreshing dip in the lake… but not so fast! Have you considered all that you would need to ensure a safe swim? Don’t be fooled by the current-free stillness that swimming in a lake presents because there are several important points to understand in order to avoid danger.

swimming in a lake

Lake Safety Concerns

Now, when I think of the dangers of swimming in a lake, the first thing that pops into my mind is Jason from Friday the 13th! However, there are actually other factors much scarier than a fictional guy in a hockey mask. Definitely stay aware of the following lake safety concerns:


Because lakes are slow moving bodies of water, the potential for algae build up becomes increased. If you swim within algae-infested waters, you run the risk of getting sick, especially if you accidentally swallow some. Although not all algae is harmful, some forms such as cyanobacteria can be a serious issue and cause any of the following: skin, eye, or ear irritation, stomach cramps, vomiting, diarrhea, sore throat, fever, headache, muscle and joint pain, or nerve and liver damage. None of that sounds like a good thing! Luckily, when toxic algae builds up, it gives off a strong, distinct smell that you should look out for. If a lake’s water has an off-putting odor, do NOT swim in it!

See the signs

State parks and other publicly-owned lands usually have their water’s quality tested by local governments. Definitely look out for any signs posted by a lake that warn about the swimming conditions. For example, a “no diving” sign would signify that a lake’s depth may be deceiving, or there are rocks or other hazards hidden right beneath the water. A “no swimming” sign would indicate that the water may be contaminated. To know for sure whether a lake you’re visiting is cleared for swimming, a fast online search on your state’s environmental websites should provide the information you need.

Near farmland

Farms and pastures are home to lots of livestock and NONE of them are potty trained! Water contaminated by fecal matter is the cause of some of the most common illnesses humans contract. Any lakes near farmland could potentially be loaded with runoff from fertilized fields or the droppings of cows and horses. Lakes like this must be tested for E. coli either by the Environmental Protection Agency or a DIY test you can cheaply purchase yourself.

Water temperature

The water in a lake is usually colder than water in a pool, which can really impede swimming. Suddenly introducing your body to cold water could cause it to go into shock which could lead to panic and potential drowning. To make sure the water is not at an unsafe temperature, dip a thermometer into a shaded section of the lake about an elbow’s length deep. Any reading below 70 degrees would be considered too cold to swim in.

Weather patterns

Seasonal changes in the weather can cause lakes to become more dangerous. Heavy rain and floods could cause open water to change in both depth and clarity. Any types of manmade bodies of water could also be empty at one point and then quickly fill up out of nowhere. The best way to combat rapidly changing weather patterns is to check the weather report and water conditions before you leave and again when you arrive. Also, always stay out of the water if you hear thunder.

Lake Safety Practices

Many lake accidents can be prevented by keeping a cool head and recognizing the right way to take part in open water swimming. In addition to staying on top of lake safety concerns, you should also remember the following key safety practices:

  • Life jackets: This should be a no-brainer, especially for younger children and infants, however even the best swimmers can miscalculate changing water conditions when swimming in an open lake. A life jacket is an ideal means for countering the risk of abruptly going underwater. Just make sure you get the right life jacket fit.
  • Swimming endurance: Always be aware of your limits as a swimmer. A lake is very different from a pool and much harder to swim in. Your body tires faster when navigating open water, which could unexpectedly lead to danger. Plus, lake water can be a bit murkier, which could lead to visibility issues.
  • Drop-offs: Look out for any abrupt drop-offs in a lake. If you are not a good swimmer, slipping accidentally into deeper water could lead to drowning, so mind your surroundings!
  • No boats: Boating accidents are one of the leading causes of lake swimming injuries. Visibility is not always clear, especially if the water is already somewhat murky. All the more reason to use a brightly colored life jacket.
  • Stand watch: It’s always a good idea to have someone on land watching the others out in the lake, especially if there are no actual lifeguards on duty. Being certified in CPR is also a very important aspect to have at the ready. 

Parting Thoughts

Swimming should be a fun recreational activity for everyone. Lakes are beautiful, relaxing products of nature and should be enjoyed in the safest way possible. To do so, please keep in mind the following helpful facets:

  • Know whether the lake you’re swimming in is infested with diseasing-causing algae by the strong smell, or E. coli by ensuring the water has been tested.
  • Keep an eye out for any signs posted near or around the lake.
  • Look out for any boats in the lake and always wear a brightly colored life jacket that is the right fit for you.
  • Be aware of your surroundings in a lake and keep track of your endurance while swimming.
  • Have someone remain on shore to keep watch, especially because most lakes do not employ a certified lifeguard.


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