Quick answer: swim at designated or well-known spots, ideally with a lifeguard, and assign a sober adult as a water watcher whenever children are in the water. Put U.S. Coast Guard-approved life jackets on young children and weak swimmers. Respect cold water, which can cause gasping and loss of muscle control within minutes, and avoid swimming in fast rivers or anywhere near dams. Stay out of water that looks like spilled paint, pea soup or scum, since the CDC warns harmful algal blooms can sicken people and kill dogs. Do not swallow lake or river water, skip swimming after heavy rain and get out of the water at the first sign of thunder.
A lake beside the campsite or a cool river after a hot hike is one of the best parts of summer camping. It is also where some of the most serious camping accidents happen. Natural water has no clear depth markings, no pool walls and often no lifeguard, and conditions change with weather, season and recent rain.
This guide covers how to choose a safe swimming spot, how to protect children, the specific dangers of cold water and rivers, and the germs and algae that can make swimmers sick. For other outdoor risks, from lightning to wildlife, see our full guide to camping safety.
Sources: Centers for Disease Control and Prevention (CDC) drowning prevention, harmful algal bloom, swimmer’s itch (cercarial dermatitis), Naegleria fowleri and recreational water illness pages; U.S. Environmental Protection Agency (EPA) harmful algal bloom guidance; U.S. Coast Guard (USCG) life jacket guidance; National Center for Cold Water Safety; National Park Service (NPS) water safety pages; National Weather Service (NWS) lightning safety; American Red Cross water safety. This article is general information, not medical advice. Checked October 2026.
Why Natural Water Needs Extra Care
The CDC reports that more than 4,000 people die from unintentional drowning in the United States each year, and drowning is a leading cause of death for young children. Many of these deaths happen in natural water such as lakes, rivers and ponds, especially among older children and adults.
Lakes and rivers bring hazards that pools do not:
- Sudden drop-offs, hidden rocks and submerged logs
- Murky water that hides a struggling swimmer
- Currents that are stronger than they look
- Cold water, even on hot days
- Algae, bacteria and parasites
- Long distances from emergency help
Drowning is quiet
Drowning rarely looks like the splashing and shouting shown in movies. A person in trouble may be upright in the water, with the head tilted back and the mouth at the surface, unable to call out or wave. This is why constant, close supervision matters more than listening for cries for help.
Choosing a Safe Place to Swim
- Use designated swim areas at campgrounds and parks, which are often roped off, checked for hazards and sometimes guarded.
- Read posted signs and campground rules. Some parks ban swimming in certain lakes or rivers because of currents, wildlife or water quality.
- Check with rangers or the campground host about recent conditions, advisories or algae warnings.
- Enter feet first the first time. Never dive headfirst where you cannot see the bottom; rocks and logs can be hidden just below the surface.
- Avoid areas with boat traffic, fishing lines or steep, slippery banks.
- Look for an easy way out of the water before you get in.
Check water quality advisories
Many state health and environmental agencies post beach and lake advisories online, including closures for bacteria or harmful algal blooms. At federal sites, NPS and the Forest Service post closures and warnings at trailheads, visitor centers and on park websites.
Keeping Children Safe in the Water
Children can drown in seconds and in shallow water. The CDC and the American Red Cross recommend several layers of protection.
Assign a water watcher
Choose one responsible adult to watch children in or near the water at all times, without phones, books or alcohol. Trade off every 15 minutes or so to stay alert, and make the handoff clear.
Use life jackets
- Put a U.S. Coast Guard-approved life jacket on young children and anyone who is not a strong swimmer, both on boats and when swimming in natural water.
- Choose a life jacket that matches the child’s weight and fits snugly; it should not ride up over the chin when you lift it by the shoulders.
- Air-filled toys such as water wings, noodles and inflatable rings are not safety devices.
Teach basic water skills
The American Red Cross describes water competency as the ability to enter water over your head, return to the surface, float or tread water, turn around, swim at least 25 yards and get out. Swim lessons in a pool are valuable, but children should also learn that lakes and rivers feel different: colder, darker and harder to swim in.
Set clear rules
- No swimming without an adult watching.
- Stay within the designated area or a set boundary.
- Always swim with a buddy.
- Get out when told, and when thunder is heard.
Cold Water Shock and Hypothermia
Many lakes and rivers stay cold well into summer, especially at higher elevations, in the north and in rivers fed by snowmelt. The National Center for Cold Water Safety describes cold water as a serious risk even in warm air.
What happens in cold water
- Cold shock: in the first minute, sudden immersion triggers uncontrollable gasping and rapid breathing. Inhaling water at this stage can cause drowning.
- Swimming failure: over roughly the next 10 minutes, muscles in the arms and legs cool and weaken, making swimming and self-rescue harder.
- Hypothermia: core body temperature drops more slowly, often over 30 minutes or more.
This sequence is often summarized as the 1-10-1 principle: about 1 minute to control breathing, about 10 minutes of meaningful movement and about 1 hour before unconsciousness from hypothermia. Times vary by person and water temperature.
How to reduce cold water risk
- Enter cold water slowly instead of jumping in.
- Wear a life jacket when boating or paddling, since it keeps you afloat through cold shock.
- Stay close to shore and keep swims short.
- Warm up afterward with dry clothes, a warm drink and shelter from wind.
Our guide to staying warm while camping in cold weather covers layering and warming up after a chill.
River Swimming Dangers
Rivers can be beautiful swimming spots, but moving water is far more powerful than it looks.
- Currents: even water moving at a walking pace can push a person off their feet. Avoid swimming in fast or rising rivers.
- Strainers: fallen trees and branches let water through but trap people. Stay away from them.
- Low-head dams: these small dams create a recirculating current below the drop that can hold swimmers and boaters underwater. Agencies sometimes call them drowning machines. Never swim or wade near a dam, above or below it.
- Changing water levels: rivers below dams can rise quickly when water is released, and rain upstream can raise levels even under clear skies.
- Slippery rocks: algae-covered rocks near waterfalls and rapids cause many falls.
If you are swept into a current, the National Park Service and many rescue agencies advise floating on your back with your feet pointed downstream, then swimming at an angle toward shore once the current slows.
Harmful Algal Blooms
Harmful algal blooms happen when cyanobacteria, sometimes called blue-green algae, grow rapidly in warm, still, nutrient-rich water. Some blooms produce toxins that can harm people and animals.
How to recognize a bloom
The CDC and EPA describe blooms that may look like:
- Spilled green or blue-green paint on the water surface
- Thick scum, foam or mats
- Water that looks like pea soup
- Green, blue, red or brown discoloration
Not every bloom is toxic, and toxins can be present without an obvious bloom, so the CDC’s advice is simple: when in doubt, stay out.
Why dogs are at high risk
Dogs often drink lake water, swim through scum and lick their fur afterward. The CDC warns that exposure to toxic blooms can make dogs sick quickly and can be fatal. Keep dogs out of discolored water, rinse them with clean water if they get in and call a veterinarian right away if they vomit, drool, stagger or seem weak. Our guide to camping with dogs has more tips for keeping pets safe.
Symptoms in people
Contact with or swallowing affected water can cause skin rashes, eye irritation, stomach upset and, in some cases, more serious illness. Rinse off with clean water after swimming and seek medical care if symptoms develop.
Other Water Germs and Parasites
Recreational water illness
Lakes and rivers can carry germs such as norovirus, E. coli and Cryptosporidium, often washed in by runoff or animal and human waste. The CDC recommends:
- Do not swallow the water.
- Avoid swimming after heavy rain, when runoff can raise bacteria levels.
- Stay out of the water if you have diarrhea.
- Take young children on regular bathroom breaks and change diapers away from the shore.
- Wash hands before eating.
Never drink untreated lake or river water. Our guide on how to find and treat water while camping explains filtering, boiling and chemical treatment.
Swimmer’s itch
Swimmer’s itch, or cercarial dermatitis, is an itchy rash caused by microscopic parasites released from infected snails. According to the CDC, it is most common in shallow, warm water near shore. Avoid marshy areas where snails live, towel off right after leaving the water and check for posted warnings. The rash is uncomfortable but usually clears on its own within a week or so.
Naegleria fowleri
Naegleria fowleri is an amoeba found in warm freshwater. Infections are very rare but almost always fatal. They happen when water containing the amoeba goes up the nose. The CDC suggests holding your nose shut, using nose clips or keeping your head above water in warm freshwater, especially during hot weather and when water levels are low. You cannot get infected by swallowing the water.
Weather, Alcohol and Other Risks
Lightning
Water and open shorelines are dangerous places during thunderstorms. The National Weather Service advises that when thunder roars, go indoors, and that there is no safe place outside in a thunderstorm. Get out of the water and away from the shore at the first rumble, and wait 30 minutes after the last thunder before going back. See our guide on camping in thunderstorms and lightning for what to do at camp.
Alcohol
The CDC reports that alcohol is involved in up to 70 percent of deaths associated with water recreation among adolescents and adults. Alcohol affects balance, coordination and judgment, and it worsens the effects of cold water. Keep alcohol away from swimming and boating.
Sun and heat
Long afternoons on the water mean strong sun exposure. Use sunscreen, wear a hat and drink plenty of clean water. Reflection off water increases UV exposure.
What to Do if Someone Is in Trouble
The American Red Cross teaches the principle of reach or throw, don’t go. Untrained rescuers who swim out to a struggling person can drown themselves.
- Shout for help and call 911 if you have a signal.
- Reach with a long pole, branch, paddle or towel while staying on shore or lying flat on a dock.
- Throw something that floats, such as a life jacket, cooler or throw rope.
- If the person is pulled from the water and not breathing normally, start CPR if you are trained and keep it going until help arrives.
Taking a CPR and first aid course before camping season is one of the most useful things a camping family can do.
Swimming Safety Summary
Swim in designated or well-known spots, enter feet first, check advisories and keep a sober adult watching children at all times. Put Coast Guard-approved life jackets on young children and weak swimmers, respect cold water and stay out of fast rivers and away from dams. Avoid water that looks like spilled paint, scum or pea soup, keep dogs out of it and do not swallow lake or river water. Skip swimming after heavy rain, get out at the first sound of thunder and keep alcohol away from the water. If someone is struggling, reach or throw instead of swimming out.
Frequently Asked Questions
Is it safe to swim in lakes while camping?
It can be, if you choose designated swim areas, check posted advisories, supervise children closely, use life jackets for weak swimmers and avoid water with algae blooms or after heavy rain.
How can you tell if a lake has toxic algae?
Water may look like spilled paint or pea soup, or have scum, foam or mats on the surface. The CDC advises that when in doubt, stay out, and keep pets out too.
What is cold water shock?
Cold water shock is the uncontrollable gasping and rapid breathing that happens in the first minute after falling into cold water. It can lead to inhaling water and drowning, so enter cold water slowly and wear a life jacket when boating.
Can you get sick from swimming in a river?
Yes. Rivers and lakes can carry germs that cause stomach illness, especially after heavy rain. Avoid swallowing the water and skip swimming when you have diarrhea.
Should kids wear life jackets in lakes?
Young children and weak swimmers should wear a properly fitted U.S. Coast Guard-approved life jacket in natural water, along with close adult supervision.
