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by Elaine K Howley

May 23, 2022

Here’s how to determine if a waterway is safe

The U.S. Geological Survey reports that about 71% of Planet Earth’s surface is covered with water. With so much liquid real estate at hand, we’re really spoiled for choice when it comes to selecting places to swim.

But venturing into a new swimming location, whether for an event or just to try out a potential new training ground, isn’t always easy. There are many safety and logistical factors to consider before taking the plunge.

Review these 10 factors to help determine whether the waterway is safe for swimming.

  • Water temperature. It’s true that extreme cold-water swimming is gaining in popularity as more people take up winter swimming or check out ice swimming events. But you should know what your own individual limits are. When trying out a new location, it’s best not to compound the potential challenge by going when the water is colder than you can tolerate. Check the temp before you plunge and be honest with yourself about whether you can handle that temperature.
  • Topography and access points. Many lakes and rivers are rimmed with sloping hills or steep banks. If the waterway you’re interested in doesn’t have an easy entry and exit point, it’s likely not worth the effort and risk of having to clamber through brambles or over slippery rocks. And while you might be able to get into the water, be sure you’ll also be able to get back out after your swim; sometimes it can be very difficult to exit a waterway if pounding surf or a steep path make combating gravity’s pull that much harder.
  • Tides. Many swimming locations, particularly sea-based ones, are subject to big shifts in water levels as the tides ebb and flow. Check the tide charts before you go and know what to expect. For example, in Boston, it’s inadvisable to swim at some swimming locations at low tide because the bay drains significantly revealing mussel beds and other hazards that can cut your feet and ruin the day. But at high tide, it’s a treat. Get to know the local conditions.
  • Currents. Seas, rivers, and lakes all have currents, and it’s best to know what you’re getting into before taking the leap into swirling or running water. Talk to locals about prevailing currents, how strong they are, which direction they go, and whether swirls or eddies tend to develop along your intended course. Plan accordingly to avoid these challenges or figure out how to work with them.
  • Weather conditions. Always check the weather before you head out to swim in open water. A pop-up thunderstorm or sudden increase in wind can make for treacherous swimming. It’s also best to find out what the prevailing wind and weather patterns are at your swimming location to help you plan the best times to swim.
  • Piers and weirs. Manmade structures such as piers, weirs, jetties, and dams can all make for very dangerous currents and conditions. Lowhead dams can be particularly dangerous, as they’re often difficult to spot but can create an inviting-looking yet treacherous place to swim.
  • Boat traffic and fishermen. Before you swim, spend some time watching the water. Are there a lot of other water users, such as boaters or fishermen out there? If so, you may want to find another place to swim. Lots of boat traffic can make for a choppy and potentially dangerous swim (if they can’t see you) and many swimmers know all too well the pain of encountering a stray fishing hook.
  • Wildlife. Another potential issue with fishermen is that they can attract larger critters who want to come steal their bait. Find out what animals you’re likely to encounter in the waterway and plan accordingly. Jellyfish are usually the worst of them, but it’s best to beware of the likelihood you’ll cross paths with anything from mosquitos to sharks.
  • Water quality. Not all water is clean enough to swim in. Check with your local water resource authority about whether the waterway you’re interested in undergoes regular water testing and whether it’s deemed safe for swimming.
  • Legal restrictions. If the area has posted NO SWIMMING signs, heed those warnings. There may be a submerged hazard you can’t see or another good reason why the location is off limits. There’s no point risking getting arrested for the sake of a swim. Move on to another, safer location.

Best Practices for Acclimating to a New Location

Once you’ve determined that a waterway might be safe to swim in, these best practices can help you get the most out of your time there and ease any lingering anxiety you might feel about breaking in a new swimming location.

  • Bring friends. The standard advice is solid: never swim alone. And this goes doubly so for an unfamiliar swimming location. Particularly for your first few scouting missions until you get comfortable in a new swimming venue, it’s also wise to bring a friend or loved one who’s willing to spot your swimming group from shore. (Even better if this person is a certified lifeguard.) This person can call if anyone gets into trouble or you need the assistance of rescue services.
  • Start small. The first few times you swim in a new-to-you location, it’s best to keep your swims short and closer to shore. As you get more comfortable with how the water moves and what other hazards might be present, you’ll learn how to manage those challenges. But especially when you’re getting acclimated, give yourself some time to learn and explore.
  • Make yourself visible. Wear the brightest swim cap you have and drag a big, brightly colored tow float so that other water users can see you as you swim. It’s so easy to lose sight of a swimmer in waves or chop, but by making yourself as visible as possible, you may be able to avoid getting hit by a boat or other adverse situations.
  • Breathe, explore, and enjoy. As you get more comfortable in a new swimming location, you can begin to stretch out and venture farther. Be sure to soak up the natural beauty of your new-found swimming hole and enjoy its quirks and unique characteristics.


  • Open Water


  • Safety