Can You Swim in a Pool with Algae in It?

Algae is a common issue in swimming pools, particularly during hot summer months or when pool maintenance is neglected. You may wonder if it’s safe to swim in such conditions, or if there are any potential health risks associated with doing so.

Can You Swim in a Pool with Algae in It

Swimming in a pool with algae can pose health risks such as bacterial infection, skin irritation, respiratory issues, and other ill effects and is NOT recommended. Proper pool maintenance involving running the pool’s circulation and filtration system, scrubbing the walls, vacuuming the debris, and shocking the pool is crucial for preventing algae growth and maintaining a safe swimming environment.

In this article, we will address the common questions and concerns related to swimming in a pool with algae, as well as provide information on how to deal with and prevent algae growth in your pool

What Is Algae?

Algae is a simple, non-flowering plant-like organism that can grow in various environments, including your swimming pool. It comes in different forms and colors, and can sometimes be mistaken for bacteria. The presence of algae in a pool can make the water appear dirty and uninviting, but understanding its types and causes can help you keep your pool clean and safe.

Types of Pool Algae

There are several types of algae that can grow in pools, each with its own characteristics:

  • Green Algae: This is the most common type of algae found in pools. It is relatively easy to treat and can be prevented through proper pool maintenance.
  • Black Algae: This type of algae is known for its sturdiness and can be difficult to eliminate. It usually grows on plaster pool walls or other rough surfaces.
  • Yellow Algae: Also known as mustard algae, it tends to cling to the shady areas of your pool. It can be more challenging to remove than green algae.
  • Pink Algae: Despite its name, this is actually bacteria that resemble algae. While not true algae, it still requires treatment to keep your pool clean and safe.

Causes of Algae Growth

Algae growth in your pool can be attributed to a few factors:

  • Poor circulation: If your pool’s water isn’t circulating properly, algae can take advantage and start to grow.
  • Unbalanced water chemistry: Maintaining the right chemical balance in your pool is crucial to prevent algae growth. Imbalances in pH, alkalinity, and other factors can create an environment that encourages algae to thrive.
  • Warm and stagnant water: Algae love warm, stagnant water. Ensuring that your pool has proper circulation and water movement can help to keep algae at bay.

Is It Bad to Swim in a Pool With Algae?

Health Risks

Algae in swimming pools can be more than just an unsightly nuisance; they can host a variety of harmful bacteria, the most common of which is E. coli. 

When swimmers come into contact with algae-infested water, there’s a risk of exposure to these bacteria. E. coli and similar bacteria can lead to infections that manifest in symptoms like stomach cramps, diarrhea, and fever. 

In some severe cases, it can lead to more serious health issues that might require hospitalization. It’s important to remember that clean, clear water doesn’t just look good—it’s also a primary indicator of a safer swimming environment.

Skin Irritation

Anyone who’s swum in an algae-filled pool might have experienced the unpleasant aftermath of itchy skin. Algae can cause skin irritations, manifesting as itchiness, redness, or even rashes for some individuals. 

The skin is our largest organ and our primary barrier against environmental threats. When it comes into contact with algae, the body might react defensively, leading to inflammation or irritation. 

For individuals with sensitive skin or existing skin conditions, the effects can be even more pronounced.

Respiratory Concerns

Certain types of algae, particularly blue-green algae or cyanobacteria, produce toxins that can be harmful when inhaled or ingested. 

When swimming in an algae-contaminated pool, there’s a risk of inhaling water droplets or mist containing these toxins. This can lead to respiratory problems such as throat irritation, coughing, wheezing, or even asthma-like symptoms in more severe cases. 

Those with existing respiratory conditions or sensitivities should be particularly cautious, as exposure might exacerbate their symptoms.

Eye Irritations

The eyes are sensitive organs, and they can be particularly vulnerable to irritations from algae-contaminated water. 

Swimming in such a pool can lead to red, itchy, or stinging eyes. The irritation might be immediate or develop a few hours after exposure. This discomfort isn’t just due to the algae itself but also to the imbalanced chemical levels often found in algae-infested waters. 

To avoid this unpleasant experience and potential harm, it’s essential to maintain pool hygiene and chemical balance.

Slippery Surfaces

Algae have a slimy texture, and when they grow on pool surfaces, they can create a slippery hazard. The pool floor, steps, and ladders can become treacherously slick, increasing the risk of swimmers slipping, falling, and getting injured. 

Such accidents can lead to anything from minor bruises to more severe injuries like fractures, depending on the nature of the fall. Regularly cleaning and maintaining the pool can prevent algae buildup and keep these surfaces safe for swimmers.

Reduced Visibility

A thick proliferation of algae can turn clear pool water into a murky green mess. This reduced visibility isn’t just unappealing—it’s also a safety concern. 

When the water is cloudy, it becomes challenging to see other swimmers, objects, or potential hazards in the pool, making collisions or accidents more likely. It’s crucial for safety reasons to ensure that pool water remains clear, allowing for easy visibility throughout.

Gastrointestinal Issues

Even the most careful swimmer might inadvertently swallow a bit of pool water now and then. In pools with algae, this can be a problem. 

Consuming algae-contaminated water can result in stomach upset, characterized by nausea, vomiting, or diarrhea. The culprits can be the toxins produced by certain algae types or the harmful bacteria they host. 

To ensure a pleasant swimming experience and to avoid post-swimming health complications, pool water should be kept clean and algae-free.

What Happens If You Leave Algae in the Pool

Algae’s Effect on Pool Equipment

If algae is not addressed promptly in your pool, it can negatively impact your pool equipment. For instance, algae can cause filters to become clogged, making them less efficient in keeping your pool clean. 

Furthermore, the presence of algae in your pool puts strain on pool pumps and circulation systems, potentially shortening their lifespan. Additionally, automatic pool cleaners might struggle to function properly and face reduced efficiency due to algae build-up.

Algae’s Effect on Pool Aesthetics and Structure

Leaving algae in the pool is not only harmful to your equipment but also to your pool’s appearance and structural integrity. Algae can stain or damage the pool’s surface, equipment, and plumbing, resulting in costly repairs or replacements.

Furthermore, the discoloration caused by algae can be stubborn and difficult to remove. Over time, untreated algae can lead to the degradation of pool finishes and materials.

For these reasons, you should strive to prevent algae from even growing in the first place, and failing that, you should also know how to remove algae from your pool.

Dealing with Algae: Eradication and Prevention

Immediate Steps for Algae Removal

If you notice algae growing in your pool, you should do the following steps:

  • Test and balance the water chemistry, especially the pH, chlorine, and algaecide levels.
  • Turn on the pump and filter system to circulate the water.
  • Remove any debris from the pool, such as leaves or dirt.
  • Brush the pool walls and floor with a pool brush to loosen the algae.
  • Vacuum the pool to remove the dead algae and any other dirt.
  • Shock the pool with a high dose of chlorine or a non-chlorine shock product to kill any remaining algae spores.
  • Run the filter for at least 24 hours to clear the water.

Preventative Measures for the Future

To prevent future algae blooms, please do the following:

  • Test and balance your water chemistry weekly, especially the pH, chlorine, and algaecide levels.
  • Shock your pool weekly with a high dose of chlorine or a non-chlorine shock product to kill any algae spores.
  • Consider using an algaecide as a preventive measure. These chemicals specifically target algae growth and can be added to your pool water on a regular basis to help keep it clear and healthy.
  • Clean your pool weekly, including brushing, vacuuming, and skimming.
  • Use a pool cover when the pool is not in use to reduce sunlight and debris.
  • Run your circulation and filtration system for at least 8 hours a day to keep the water clear and sanitized.

Seeking Professional Help

If you have taken the necessary steps to eradicate and prevent algae but are still facing issues, it may be time to seek professional help. Pool maintenance experts have the knowledge and resources to identify and treat stubborn algae problems. 

They can also provide recommendations for maintaining proper water chemistry and sanitation practices for your specific pool type and environment.

Remember to keep your pool clean, chemically balanced, and free of debris to minimize the risk of algae growth. With consistent care and maintenance, you can enjoy your pool safely without the worry of algae interfering with your swimming experience.

Common Myths About Swimming in Algae-Infested Pools

In this section, we’ll debunk some common misconceptions about swimming in pools with algae. By understanding the truth behind these myths, you can ensure a safer and healthier swimming experience.

Myth 1: A Little Algae Is Harmless

It’s easy to assume that a small amount of algae in your pool isn’t a big deal. However, any presence of algae can be harmful. Algae growth can lead to serious health risks for swimmers, such as skin irritation, eye infections, and respiratory issues. 

Moreover, some algae types can even cause severe illnesses like meningitis. So, even a little algae in your swimming pool is not harmless and should be addressed immediately.

Myth 2: Chlorine Alone Can Kill All Types of Algae

Chlorine is often used to sanitize pool water and can effectively eliminate certain types of algae. However, it is not a universal solution. 

Some algae, like black and mustard algae, are more resistant to chlorine and may require additional treatments, such as algaecides or thorough scrubbing, to remove them. 

It’s essential to understand the types of algae in your pool and ensure you are using the correct methods to address them effectively.

Myth 3: Algae Is Just a Visual Concern

Algae in your pool might be unsightly, but its dangers go beyond aesthetics. Aside from the potential health risks, algae growth can also impact your pool’s overall function and maintenance. 

For example, algae can clog your pool’s filter system, causing it to work harder and eventually wear out. Furthermore, the bacteria and other organisms harbored by algae can damage your pool’s surfaces and equipment if left untreated.

Do not underestimate just how damaging algae can be on your pool, and more importantly, your health and those of anyone else using your pool. Take preventative steps to ensure pool algae doesn’t get into your pool, and if it somehow still does, treat it ASAP!


Photo Credit: nikpawlak (CC BY-NC-ND 2.0)