If you’re a pool owner who has a hazy pool, you’ll obviously want to know, “Why is my pool cloudy?”. And, the next question will be, “How can I clear the cloudy pool?”. Well, this article will help you understand the causes, cure, and the preventive measures to keep your pool clear and healthy. 

Before you deal with the cloudiness, you need to determine what caused your swimming pool water to become cloudy in the first place. Once you’ve figured out what’s causing the problem, you can take steps to fix it. 

After all, everyone likes to have an inviting pool with clean and clear water in their backyard. Apart from being unsightly, a dirty pool is a threat to your safety and good health too.

Read more: Types of swimming pools for your home

What does a cloudy swimming pool mean?

cloudy ground pool

Basically a cloudy pool is where the water looks milky or has a murky, unsightly appearance. The cloudiness is because of the presence of tiny particles – whether due to a chemical imbalance, poor filtration, or environmental factors – that reflect back the sunlight. While these particles are too small to be seen (ranging from 0.5 to 5.0 microns), they do cause varying degrees of cloudy pool water.

  • Dull water: Where it loses its sparkle and luster.
  • Hazy water: Where you may be able to see the bottom of the swimming pool but that’s about it.
  • Cloudy: Where your pool water starts to look milky, making it difficult for you to see the bottom of the pool.
  • Opaque: Where the water makes it difficult for you to see through. 

Is swimming in a cloudy pool safe?

Cloudy pools don’t just take away the aesthetic appeal from your yard , they are also dangerous to swim in. Especially if the cloudy pool water is because of the ineffectiveness of chlorine – leading to an increase in the presence of pathogenic bacteria and organisms such as E.coli and pool algae.

Furthermore, swimming in a cloudy pool can cause irritation to the eyes and skin, as well as stomach issues and urinary tract infections.

A cloudy pool could also indicate high chloramine due to the presence of contaminants such as urine, feces, blood, sweat, and dirt in the pool.

Also, the cloudiness may limit the view of those supervising the swimming sessions. That is to say, amateur swimmers will be less easy to spot and may be susceptible to danger.

Why is my pool cloudy?

indoor pool cost

There can be several answers to the question, “Why is my pool cloudy?”. Some of the most probable reasons include:

Poor filtration

If your pool filters are not working properly, or are clogged, it could mean very dirty, stagnant water. Keep in mind that regular cleaning and maintenance will keep your pool’s circulation system running smoothly.


  • Check if your pool filter has a clog or build-up. If yes, then clean your filter, D.E. grids, or the cartridge in your filter. 
  • Remove any debris, leaves, or twigs from your skimmer basket or pump basket. 
  • Check if the pool pump or filter needs replacement. 
  • Replace your pool filter media if it’s worn out or damaged.
  • Change your filter sand every 5 years.
  • Replace your cartridge filters every 2-3 years. In case of a D.E. filter, add fresh diatomaceous earth powder.
  • Run your pool filtration system for at least 8 to 12 hours a day. 

Improper chlorine level or PH levels

Imbalanced pH levels render the free chlorine ineffective or less in quantity. Less amount of free chlorine results in chloramine (combined chlorine level) which is both irritating and corrosive. With insufficient chlorine, there can be a growth of pathogens, and bacteria. For the uninitiated, the combined chlorine level is the difference between the free chlorine reading and the total chlorine reading. 

Chlorine is not properly stabilized if there’s debris in the pool, if there’s a build-up of bodily contaminants such as sweat or sunscreen, or if the pool water is exposed to the sun’s UV rays. That’s because the harsh rays break down chlorine. 


  • Test your chlorine levels – both free and combined – by using test strips, a liquid test kit, or you could take a sample to your local pool supply store. 
  • Make sure the total amount of the free chlorine plus combined chlorine is between 1 and 3 ppm (parts per million) if you have a chlorine or salt water pool.
  • Add shock (with calcium hypochlorite shock) to rebalance the chlorine levels. You can do so once a week during peak pool season. 
  • Add cyanuric acid to stabilize a sun-exposed pool. Make sure the CYA levels are between 30 and 50 ppm.
  • Ensure that the combined chlorine level is below 0.5 ppm or just under 0 ppm.

Too alkaline

Pool water that has a high total alkalinity level or TA (higher than 200 ppm) tends to become cloudy. The imbalance in the pH levels can lead to calcium scaling or calcium hardness on your pool surface and plumbing – besides of course rendering the chlorine less effective.


  • Balance your pH level, TA, and calcium hardness levels – keeping the pH between 7.4 to 7.6.
  • Keep the alkalinity level within the range 100 ppm to 150 ppm. You can use muriatic acid or a pH decreaser to lower it and baking soda to increase it.
  • Make sure the calcium hardness is 175 ppm to 225 ppm for vinyl liner pools and 200 ppm to 275 ppm for concrete and plaster pools. For high calcium hardness levels, you should dilute the pool water – partially draining the water and refilling with fresh water from a garden hose filter. 

Contaminants, environmental debris, and algae

cloudy pool

Cloudy water can be caused by contaminants, particles, and microscopic debris in your pool. This is especially prevalent in the spring. The most common contaminants are sunscreens, body oils, make-up, perspiration, and bodily fluids. These result in a cloudy pool. Cloudy pool water can also be caused by early-stage algae growth.


  • After a heavy rain or storm or when debris or pollen builds in your pool, test, balance, and clean it. Keep in mind that rainwater can contaminate your pool water with nitrates, phosphates, and other chemicals. And, also dilute your chlorine levels.
  • Skim, brush, and vacuum your swimming pool to remove any algae. And, then, shock your pool. 
  • Remove environmental debris such as leaves, twigs, pollen, dust, flowers, and bird droppings. Any of these can build up in your pool filter and make the water turn cloudy.
  • Make sure your pool filter and pump are suitable for the size and location of your pool.

Read more: How to remove pool algae

Preventing cloudy pool water in the future

The problem doesn’t end with just clearing the pool water. As a pool owner, you have to take steps to prevent the issue from recurring. Here are a few important steps to prevent cloudy pool water.

  • Check the jets and position them downward to ensure proper circulation through the filtration system.
  • Use a pool clarifier to deal with environmental contaminants.
  • Test the pool water twice a week to ensure a balanced chemical composition. If there’s a chemical imbalance, add the appropriate pool chemicals.
  • Make sure the pH level is within 7.2 to 7.6 and the chlorine concentration is within 1 to 3 ppm.
  • Let the pump run for at least 8 hours out of 24 hours. 
  • Use pool shock weekly during moderate use.
  • Check your filter and pump to ensure they’re working properly.

Read more: Pool screen repair

Last thoughts

A cloudy pool with murky water can be a buzzkill. If you own a pool in your yard, chances are you’ve struggled with this issue often and asked yourself, “ Why is my pool cloudy?”. Well, hopefully the answer to that problem is now clear to you.

Before you fix cloudy pool water, it’s important to find the root of the problem. And once you do, you can take steps accordingly. Keep in mind that owning a pool means making sure the water is safe and clean for the swimmers. That’s why, you need to conduct regular, routine pool maintenance and ensure proper filtration. 

Read more: Swimming pool financing

Why is my pool cloudy? Solve the problem like a pro was last modified: September 26th, 2022 by Ramona Sinha
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This is why a pool is a commitment, it requires a lot of care