How to Clear Cloudy Pool Water

5 Reasons Your Pool Has Cloudy Water and How to Fix It

Frustrated with cloudy pool water? Here are five reasons it’s happening and proven fixes so that you can get back to enjoying your pool.

In the course of owning and trying to enjoy your pool, it’s almost inevitable that you are going to run into the problem of cloudy pool water.

There are several primary reasons that the pool water has gotten cloudy.

Here are the principal offenders:

  • Insufficient chlorine.
  • Unbalanced pool chemistry.
  • Low filtration.
  • Debris and contaminants in the water.
  • Inclement weather (heavy rain, etc)

For new pool owners, cloudy pool water can be a little intimidating. I get it. There’s lots of lingo and sciencey words involved.

Phosphates. Cyanuric acid. Calcium hardness. Science, science, and more science!

But fear not.

Once you get a clear (see what I did there?) idea of how your pool works and what it needs to function optimally, cloudy pool water will become a thing of the past.

How to Diagnose and Fix Cloudy Pool Water (Step-by-Step)

Here’s what you need to know about diagnosing and fixing cloudy pool water.

1. Insufficient chlorine.

Everybody knows what chlorine is and what it does for swimming pools, and yet, it’s staggering how often cloudy water can be quickly fixed simply by optimizing the chlorine levels in the water.

When chlorine is low, all the stuff that causes cloudy pool water—algae, bacteria, bodily fluids like oil and sweat—have free reign on the pool.

Next time you have a group of people in your pool, notice how quickly the water quickly gets “foggy”—it’s not just leaves and dead insects that cause this issue.

Sunscreen, oily skin, and sweat “burn up” chlorine.

(So does excessive exposure to sunshine—UV rays degrade chlorine over time.)

How to Fix:

The fix, in this case, is easy enough:

  • Test the water. Pull out your handy pool testing kit, whether it is a set of pool test strips or a digital tester for pools, and check the free chlorine levels.
  • Shock the water. Shocking the water is a simple matter of adding enough chlorine to the pool to drop-kick all the bacteria and chloramines causing cloudy water. Pool shocks temporarily raise the chlorine levels to kill off contaminants.

Once this is done, let the pool pump circulate the water and sit back poolside for a few hours.

In the future, load up some chlorine tablets either in your basket skimmer or in a floating chlorine dispenser to ensure that your pool is getting the cleaning it requires.

How to Fix Cloudy Pool Water

2. Test the water

While we have that pool test kit out, we may as well take a gander at the other key markers of pool water health.

These include:

  • pH. When the pH is off, it can affect how well your pool chemicals are functioning. Look for a pH in the range of 7.4 to 7.6.
  • Alkalinity. This measure tells you how well pH is being stabilized, so it is usually the first thing you want to look at when testing the water. Most above-ground pools, which are made of vinyl, should have a range of 100-140.
  • Calcium hardness. If calcium levels are too high, this can cause structural integrity problems with the plumbing and equipment in the pool. Generally, the only step you can take here is to dilute the water by partially draining the pool and topping it off with new water.

Testing the water regularly is something you should be doing and will help you catch potential problems like cloudy water in your pool.

3. Low or poor pool filtration.

The workhorse of your pool cleaning is the pump and filter.

They work up to 12 hours a day, collecting junk from your pool while you are sleeping, doing the grunt work of keeping the water clean.

But when issues arise in the filtration system, the water doesn’t get cleaned properly.

Fortunately, this problem is usually not that complicated to fix.

How to Fix:

Here are the three simple steps to resolving this issue:

  • Clean the pool filter. If you have a sand filter, backwash it. If it’s a cartridge filter, rinse it off. Pool filters clean your pool water, but you have to remember to clean it, too.
  • Empty the skimmer basket. All the organic matter and debris that the filter collects gets dumped somewhere. When it’s full, the filter can’t do its job at full tilt, slowing down filtration, leading to water that is cloudy. Empty the skimmer or pump basket.
  • Run the pump and filter for longer. Often, pool owners will cut down the time their pump is running to save on energy costs. Make sure the pump and filter are running according to the volume of your pool.

If these fixes don’t resolve the cloudy pool water, it might be time for replacing the filter and pump or the filter media.

4. Contaminants in the water

Swimming pools are a heaping spoonful of fun, but in all that excitement to cannonball into the water swimmers tend to forget that they are tracking in a lot of dirt, grass, mud, and other organic debris into the water.

Add that to the insects, leaves, twigs, and other miscellaneous stuff that falls into the pool, and it doesn’t take long for your pool chemicals to become overwhelmed.

From there, it’s not a long trip to algae growing on the sides and wall of the pool and cloudy water.

How to fix:

  • Skim, scrub, and vacuum the pool. Fixing cloudy pool water requires giving the pool a skim and scrub. Deploy your pool brush to “shave” algae off the walls. Use the pool skimmer to collect stuff on the surface. And unleash your pool vacuum to suck everything else out.
  • Consider using an algaecide. For pools that are part milky and cloudy and part algae, take a look at an algaecide. There are excellent pool algaecides on the market you can use for both treatment and prevention.

When it comes to keeping organic refuse out of the pool, make sure to consistently use a cover for your pool (even a solar pool cover can be helpful).

5. Inclement weather

Finally, we have our last leading cause of cloudy pool water—yucky weather!

Rain can be great in a lot of respects: waters the lawn, gives us a respite from streaks of blindingly hot summer days, and in the right conditions, can be quite refreshing.

But when heavy rainfall hits our swimming pool, it starts to mess with the pool chemistry.

Added water dilutes our pool chemicals, weakening their ability to do its job properly, and rainfall is usually accompanied by falling debris, compounding reason #4 for cloudy pool water.

If you notice that the pool water has turned cloudy after a couple of days of hard rain and windy weather, bust out your trusted test kit and measure the chlorine and pH levels.

This will usually solve the present dilemma, but properly covering the pool when it is not in use will help prevent cloudy pool water from storming back your way again.

How to Clear Cloudy Pool Water
Next stop– Cannonball-town!

Frequently Asked Questions About Fixing Cloudy Pool Water

Why is my pool still cloudy after shocking it?

Shocking the water—even though it sounds like an immediate task—takes time. While pool shock starts to work quickly, it can take time for free chlorine to do its job properly.

Additionally, if you are shocking the pool using unstabilized chlorine during the daytime, you are degrading and burning off a significant amount of the chlorine.

UV rays break down chlorine, so if you are going to shock the pool to treat cloudy pool water, do so at dusk so that the shock has time and a UV-free environment to do its thing.

Can I swim in a cloudy pool?

I wrote a more detailed post about whether it’s safe to swim in a cloudy pool here that detail the risks and how to make a judgment call on whether the water is safe to swim in, but to summarize, a light haze in the pool is still relatively safe.

Once the pool gets cloudier, and especially if the water becomes milky, the risk for infection and irritation increases significantly.

Whether the pool is hazy from a swimmer wearing too much sunscreen, or the pool water is so cloudy you cannot see the bottom, you should still treat it.

How long should I want to swim after shocking a cloudy pool?

Shocking the pool is your fastest ticket for clearing a cloudy pool. At the bare minimum, you should wait 24 hours after adding a bunch of pool chemicals before swimming.

Elevated chlorine levels can be an irritant and a respiratory hazard, so give your pool a chance to come down to normal chlorine levels of 1-5ppm before jumping in.

Wrapping It Up

Cloudy pool water is one of the most consistent foes you will have in your time as a pool owner. The reality is that it will happen from time to time, whether it’s because you didn’t balance the water properly one week, or the filter is clogged up, or simply because you had a big pool party on the weekend and the pool saw a lot of use.

Whatever the case, you have a step-by-step plan for addressing it at your disposal now, so go clear that pool water with confidence and get back to enjoying your swim pool!

More Pool Maintenance Guides

How Hard is it to Maintain an Above-Ground Pool? Not as hard as you think–here are the basics of keeping your above-ground swim pool clean and functioning optimally.

6 Best Variable Speed Pool Pumps. Frustrated with big electricity bills from your backyard pool? Replace your standard pool pump with one of our favorite cost-saving variable speed pool pumps.

6 Best Pool Cover Pumps for Protecting Your Swim Pool. The right pool cover pump protects your pool by clearing water and snowmelt from the top of your swimming pool. Here’s a detailed look at the best pool cover pumps on the market right now.

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Olivier Poirier-Leroy Olivier Poirier-Leroy is the founder of He is an author, former national level swimmer, two-time Olympic Trials qualifier, and swim coach.

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