Yuck! Your Favorite Swim Spot Is a Lot Grosser Than You Realize


Water is supposed to clean us off — but are popular swimming spots as clean as we think? (Photo: Stocksy/JP Danko)

Water is supposed to purify: Taking a shower, washing your face, and staying properly hydrated promote good hygiene and health. But sometimes water is the one that gets dirty. That’s why since 1972, when The Clean Water Act was passed, the U.S. Environmental Protection Agency (EPA) has regulated both water pollution and quality standards in an attempt to keep our H2O clean.

And since summer is prime time for swimming, you may be wondering just exactly how clean the water you jump in really is. To fully understand that, you need to understand how water pollution is gauged — and how dangerous it is.

The effects of swimming in polluted water can range from mild to severe depending on the toxin or pathogen, the length of exposure, and concentration of pollutant, Rachel Silverstein, PhD, Executive Director and Waterkeeper of Miami Waterkeeper, tells Yahoo Health. You could get sick from ingesting dirty water, getting it in your eyes, or by simply letting it come into contact with your skin.

“Illness could include symptoms such as intestinal upset, infections, respiratory issues, rashes, flu-like symptoms, and in some extreme cases, death,” Silverstein says.​ The best thing to do? Avoid polluted water — and especially if you have open cuts or sores, she says. (But if you do think you’ve come into contact with contaminated water, rinse it off with soap and clean water and take a proper shower as soon as you can. And make sure to see a doctor if you start to feel sick.)

Understanding the Different Types of Pollution

Water pollution is broken up into two categories: point and nonpoint pollution, Monica Lee, a spokesperson for the EPA, explains to Yahoo Health. Think of point sources as single sources like pipes or ditches going directly into the water.

Meanwhile, nonpoint pollution comes from sources like rainfall or snowmelt, she says. “As the runoff moves, it picks up and carries away natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters, and even underground sources of drinking water.”

Sources of nonpoint pollution can be harder to track — and thus, even more damaging to our water sources. The main threats to our water are fertilizer runoff (i.e. golf courses), farms (fertilizer, manure, pesticides, bacteria), energy-producing industries (i.e. coal or nuclear plants), chemical inputs from industry, stormwater (fuel, oil, feces), septic tanks, and sewage spills, among others, says Silverstein. Sewage and other fertilizer pollution can also lead to toxic algae blooms and may promote growth of pathogens (bacteria and viruses) in ponds, lakes, oceans, and rivers, she says.

When a body of water is considered clean, it’s not just absent of these pollutants — it also has an intact ecosystem that can deal with low levels of pollution through “absorption by plants and filtration through sandy bottoms or porous rock,” she says. “Wetlands can reduce nutrient pollution from sewage or fertilizer runoff, too, since aquatic plants absorb the nutrients as they grow, thereby cleaning the water.” That’s why in places like Arizona, wetlands are used in conjunction with industrial sewage treatments to help clean the water naturally and provide habitat for wildlife.

There’s no hard and fast rule as to which bodies of water are better or worse when it comes to pollution. It’s all very site-specific, Steve Fleischli, the Water Program Director for the Natural Resources Defense Council (NRDC), tells Yahoo Health. Some states also do a better job than others at posting about dirty beaches, closing bodies of water, and collecting samples. The NRDC’s annual Testing the Water Report keeps track of where states rank in terms of contamination, how often they close contaminated beaches, and how much they prioritize water testing. (See how your state stacks up here.)

But considering location, size, and pollution sources can help you understand what could be going on in your local watering hole.

How Dirty Are Oceans?

Runoff — particularly from urban or agricultural areas — is one of the biggest sources of pollution of oceans, according to the National Oceanic and Atmospheric Administration. When it rains, pollution from city streets or agricultural areas can make its way toward the water. So if there are no large agriculture sources or urban outputs near the area, you’re more likely to see clean water in nearby rivers, lakes, and oceans.


The water at the beach may not be as clean as you think. (Photo: Stocksy/Natalie Jeffcott)

Of course, there are exceptions. Take Venice Beach in California. Fleischli says it’s a fairly clean beach even though it’s in an urban area. That could be because the area of land that drains to this beach is small. (The larger the area that drains to a beach, the dirtier it is.)

Sewage overflows — either from aging systems, leaking pipes, or malfunctioning plants or pumps — can also pollute ocean, bay, and Great Lakes beaches. A malfunctioning wastewater plant “can quickly spill millions of gallons of partially treated sewage into coastal waters and result in no-swimming advisories along miles of beaches,” according to the NRDC.

Related: Deadly Vibrio Vulnificus Bacteria Kills Florida Swimmer: Are You in Danger?

The size of a body of water can also be a factor in how polluted it is, particularly when it comes to the Total Maximum Daily Load (TMDL) — the maximum amount of a pollutant that a body of water can receive and still safely meet water quality standards. Larger bodies of water can have higher amounts of contaminants and still meet water quality standards since the pollutant isn’t as concentrated, though some larger bodies of water (like oceans) also circulate and dilute pollution more, says Fleischli.

But better circulation is not a solution: “’Dilution is the solution to pollution’ used to be the saying. But that is very wrong. Keeping pollution away is answer,” Fleischli says. After all, even given size and circulating ability, scientists are seeing pollution issues in oceans on the rise, as oceans lose their ability to absorb increasing levels of pollution, Silverstein says.

How Dirty Are Rivers?

Agricultural pollution affects nearly 40 percent of the country’s tainted rivers and streams. Again, the idea comes back to ecosystems — and some small or stagnant bodies of water with intact ecosystems may absorb pollution better, and be cleaner as a result, than fast-moving rivers near industrial areas, says Silverstein.

The 2008/2009 National Rivers and Streams Assessment found that 40 percent of rivers and streams had too-high levels of phosphorus and 28 percent or more had excess levels of nitrogen, she says. Excess phosphorus and nitrogen can signal nutrient pollution — which can cause algae to grow faster than a body of water can handle, thus harming water quality and ecosystems. This can also wind up cutting the amount of oxygen in the water, which fish need to survive.

How Dirty Are Lakes and Ponds?

While it’s hard to generalize, areas that are more sheltered or where water doesn’t move quite as much — like the Great Lakes — are more prone to elevated levels of pathogens, Jon Devine, senior attorney with the NRDC’s water team, tells Yahoo Health. “Areas located near discharges — like stormwater outfalls — are more likely to have problems, too,” he adds.

The NRDC states that “combined sewer systems, concentrated in the Great Lakes region and the northeastern United States, carry both raw sewage from homes and businesses and stormwater runoff from streets to sewage treatment plants.” Usually, that’s OK. But when rainstorms hit, combined wastewater can become too much for a treatment plant to handle. So the excess flow — which includes raw sewage, toxic industrial waste, and trash — is discharged from outfall points and into the most nearby stream or coastal waterway. This excess flow (called combined sewer overflow is a “major cause of pathogen contamination in marine and Great Lakes waters,” the NRDC says. Warmer temps in these regions can also lead to green algae called Cladophora. In a worst-case scenario, this algae can become breeding grounds for E. coli.

How to Spot Dirty Water

Figuring out if a body of water is clean or not isn’t as easy as seeing how clear it is. Silverstein says the Colorado River, for example, is supposed to be murky. ​That’s because some bodies of water naturally have more suspended sediments (or sand) in the water due the natural geology or ecology of the region, she says. That doesn’t mean that it’s “dirty” in terms of pollution or impacts to human health. Plus, Fleischli says that he’s seen beaches he was convinced were contaminated, but actually weren’t. Here’s what to look out for to properly ID polluted water:

  • Look for signs. “Maybe the best sign is literally a sign,” says Fleischli. “A lot of beaches will post signs that say ‘No Swimming,’ or state that the water is contaminated. It sounds pretty simple, but if you see a sign telling you not to swim, don’t swim.”

  • Take note of the boats. Boats can be a sign of pollution because of the inputs coming into the water, says Fleischli. “Some harbors are fairly dirty,” he says, adding that the fix could be as simple as driving a little further out to a more remote area. One boat is not a big deal, but harbors tend to have lots of boats that reside there on a permanent basis, he says. “It is the bathroom waste on those boats that might leak or that might get pumped into the water, rather than properly being disposed of, that’s the concern.”

  • Wait the rain out. “Rain is going to wash pollutants and urban slobber down and can cause sewer overflow,” says Fleischli, who suggests waiting three days post-rainstorm to swim in an ocean, lake, or pond if large drains are nearby.

  • Analyze beach names. Ever see beaches with names like Mother’s Beach or Kiddie Beach? These names usually hint at stagnant water and no waves, which can create a stagnant environment for pollution to sit, Fleischli says.

  • Be in the know. Heal the Bay, a West Coast non-profit environmental group, has a rating system and daily beach reports for West Coast beaches; the Waterkeeper Alliance Swim Guide App provides the latest water quality information for East Coast beaches; and the Testing the Waters Report offers a deep history of pollution at thousands of beaches, including the Great Lakes.

  • Look for drains. “Never go swimming in front of a sewer outfall or a pipe draining into water,” says Fleischli. Raw sewage can leak out of these pipes when it’s raining. One Heal the Bay study found that you’re safer 100 yards from a flowing drain than swimming right in front of it.

  • Sniff around. “Your first indication of polluted water might be a bad smell,” says Silverstein. “I’ve been swimming in bodies of water that have smelled of sewage and you know right away that something is wrong.” She adds that bad algae blooms can smell, too. Some kinds might be natural, but a bad smell can be a sign of unhealthy growth.

What About Swimming Pools?

Since pools are packed with chlorine, they have to be clean, right? Not so fast. A 2010 report from the Centers for Disease Control and Prevention (CDC) found about one out of every eight public pool inspections conducted in 13 states resulted in pools being closed immediately due to serious code violations, including no measureable disinfectant, says Mary Ostrowski, Senior Director of Chlorine Issues at the American Chemistry Council, a trade association.


Just because pools have chlorine doesn’t automatically mean they’re clean. (Photo: Flickr/Thomas Hawk)

But your pool isn’t doomed for dirtiness. “Unlike ocean, lake, or pond water, pool water quality can be controlled rather directly,” Ostrowski tells Yahoo Health.

Good pool water quality is determined by two things: proper pool chemistry management and good hygiene, she says. Think you couldn’t possibly be contributing to a pool’s pollution? Know this: “On average, 0.14 grams of feces are washed off the skin of each swimmer who enters a pool,” says Ostrowski. That’s not just gross — it’s dangerous, considering fecal matter contains pathogens. Most of the time, disinfectants help destroy them (including Shigella, E. coli, viruses such as norovirus, and the protozoan Cryptosporidium) — but improperly chlorinated water puts you at risk for diarrhea and ear and skin infections, Ostrowski says.

Related: Is Peeing in the Pool Really All That Bad?

Make sure you shower before getting into the pool to reduce your part in the pollution. And rather than worry about pathogens (a well-maintained pool will destroy them), check for the signs of a healthy pool, says Ostrowski. If it’s your pool, use test strips to check water pH and chlorine levels. If you’re somewhere public? Follow these guidelines:

  • Look for clear. You should be able to see clearly through the water to the floor of the pool.

  • Listen for pumps. If you’re near the mechanical room, you should be able to hear the pool pumps operating to circulate the pool water, says Ostrowski. “For larger pools, pumps might not be as audible. In that case, you should be able to feel water being pumped into the pool in various locations, especially near the bottom.”

  • Chemical smells = no good. “A properly maintained pool should have no harsh chemical odor,” she says. While you may attribute a strong smell to chlorine, it’s usually the smell of substances called chloramines, which can irritate your eyes and skin, Ostrowski says. “Chloramines form when chlorine combines with impurities like perspiration and urine.” It gets worse, too: Chloramine depletes chlorine that could otherwise be working to destroy germs, she says.

  • Slime is bad. The tiles on the sides of a pool should feel smooth and clean, not slimey, which would indicate biofilms — a group of bacteria that stick to each other on a surface, she says.

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