Signs That Your Swimming Pool Needs a Deep Clean

Written by Michael Dean
February 14, 2024

very dirty swimming pool

Swimming pools require constant maintenance – from cleaning, vacuuming, and skimming to balancing chemicals, and so much more. Despite the routine maintenance tasks, every now and then, your pool may still require a deep clean. But when is it time to deep clean your pool?

Below, I cover the common signs to look for when your pool is unsafe to swim in and needs a thorough cleaning.

Main Takeaways

  • Some signs that your pool needs a deep clean include: strong smell of chlorine, badly out-of-line chemistry, cloudy water, green water, discolored water, foam, living organisms in your pool, the pool is full of debris, and the filter is backed up and dirty.
  • While the smell of chlorine is often associated with a clean pool, it is actually the opposite. A safe pool has no chlorine odor.
  • Depending on the chemical you add to your pool, wait between 15 minutes to 24 hours before jumping back into the water.

Sign #1: Strong Smell of Chlorine

Contrary to popular belief, a strong smell of chlorine does not mean your pool is safe. In fact, a healthy, safe pool will have little to no odor. That smell comes when your pool is out of balance. The smell of chlorine arises when the chemicals are dealing with a lot of organic material like sweat, urine, and bacteria in your pool. As the chlorine tries to deal with the contaminants not being filtered and cleaned sufficiently, it causes chloramine, which makes that smell. A strong smell does not mean there is too much chlorine in the pool; it means there is not enough to deal with all the contaminants.

Sign #2: Badly Out of Line Chemistry

Part of your swimming pool maintenance checklist is regularly checking the chemistry and keeping a healthy pH, alkalinity, calcium, and free chlorine or bromine levels. If these numbers are badly skewed, immediate work is needed. Check out my guide on swimming pool chemistry to learn how to do the appropriate checks.

pH and Alkalinity

Your pH should lie between 7.2 and 7.8, and your alkalinity should be between 80 and 120 parts per million (ppm). If your pH and alkalinity are not balanced, balance them immediately with the help of chemicals like sodium bisulfate and sodium bicarbonate.


If you have a concrete or plaster pool, calcium hardness levels should be between 200 and 275 ppm. And if you have a vinyl or fiberglass pool, the calcium in your pool should be 175 to 225 ppm. If you have too low calcium levels, this can turn your water acidic, which can harm your pool. On the flip side, if you have too high calcium levels, you’ll find scale buildup in your pool, including in your pool plumbing!

Chlorine or Bromine

Of course, your pool needs the right amount of sanitizer to be safe and clean. If you have a chlorine pool, the levels should be 1 to 3 ppm; if you have a bromine pool, the levels should be 3 to 5 ppm.

Sign #3: Cloudy or Murky Water

Cloudy water indicates a chemical imbalance and a lot of particles in your pool. It can be a sign of heavy rain, lack of sunlight, insufficient filtration, or poor water circulation. Time to do something about it! Read my guide on clearing cloudy pool water to learn how to clear everything up.

Sign #4: Green Water

This is a sign of algae growing in the water and on the sides and bottom of the pool. Read my guide on how to clear green pool water to get rid of it easily.

Sign #5: Discolored Water

Unhealthy pool water can be colors other than green. The most common is brown or yellowish. This can be from brown algae growth or other contaminants in the pool. Any color change is a serious sign that something is out of order and needs to be corrected.

Sign #6: Bubbles or Foam

Having too many bubbles or a layer of pool foam means your water has enough contaminants to keep long-term bubbles due to strong surface tension. This can be caused by substances like lotions, sunblock, soaps, etc., in the pool, a high concentration of bacteria, a chemical imbalance, having way too many chemicals in the pool, or clogged filters.

Sign #7: Living Organisms in the Pool

Uncared-for pools can become breeding grounds for bacteria and creatures like mosquitoes, larvae, water beetles, and other small life forms. Do not swim in a pool where you see small things wiggling in the water. Seek professional assistance.

Sign #8: Pool Is Full of Debris

You should skim and clean your pool every day, but if you have too much debris in it, either due to a major storm or neglect, it’s time for a much-needed clean! Check out my pool cleaning guide to discover how to do this effectively, which includes skimming out leaves or other debris and vacuuming sediment from the ground.

Sign #9: The Filter Is Backed Up and Dirty

The filter is an absolutely essential part of your pool health. If this filter is backed up and dirty, it won’t be able to do its job. This will lead to stagnant and dirty water that is dangerous to swim in. Make sure to clean your filter as needed. Generally, it is time to clean your filter when the pressure reads 8 to 10 psi above the normal range. Properly maintaining the filter is also necessary.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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When Is It Safe to Swim in Your Pool After Cleaning?

In general, different chemicals have different wait times. The wait times can range from 15 minutes to 24 hours, depending on the harshness of the chemical. Some chemicals are safe to swim in, while others can cause burns on your skin. After shocking your pool or doing a deep clean, you should test your chemistry to ensure it is balanced before swimming in it to ensure it is safe.

Here are some pointers for specific chemicals and treatments:

  • Wait at least 20 minutes to an hour after adding water-balancing chemicals such as pH, alkalinity, or clarifier.
  • Most algaecides are safe to swim in, but it’s a good idea to wait at least 15 minutes before you jump in your pool.
  • Always test the water after shocking your pool, but swimming is generally safe after the chlorine levels are around 5 ppm or after 24 hours.
  • Muriatic acid can burn your skin, so it is best to wait at least 30 minutes after adding it to your pool.
  • It is recommended to wait for a full cycle through the filter or at least 2-4 hours after adding calcium chloride.
  • Testing your pool is the best way to determine whether you can swim in it after adding liquid chlorine, but it’s generally safe to enjoy your pool after waiting about 4 hours or until the level reaches 5 ppm or lower.
  • After adding flocculant to your pool, you should only swim in the pool after the floc has been vacuumed from settling to the bottom of the pool. Otherwise, it loses its effectiveness.

Don’t Forget to Clean Your Pool

Cleaning your pool is an essential part of pool maintenance. You should clean your pool every day, but every now and then, if you spot any of the above issues, you’ll need to roll up your sleeves for a deep clean. While it can seem like a pain, the effort is worth it in the long-run, as you’ll be able to enjoy your clean and sparkling pool for longer!

Have questions about any of these issues or cleaning your pool? Shoot me a message, and I’ll be happy to help.

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