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How Much Pool Evaporation Is Normal?

Natural evaporation is an essential part of maintaining a pool. The added water dilutes harsh chemicals, such as cyanuric acid, calcium, and high levels of chlorine.

However, too much evaporation could be a sign of a leak or unprotected water. It’s important to know how much evaporation is normal and what’s considered excessive.

Normal pool evaporation ranges from ¼” to 1” a day, depending on the outside temperature and the chemicals in the pool. Solar covers and liquid solar balls limit evaporation, but they can’t stop it altogether. If your pool is losing more than a couple of inches of water daily, there could be a leak.

Throughout this article, I’ll explain how much water should evaporate out of your pool, why your pool loses water so quickly, and how to know if your pool is leaking or evaporating.

How Much Pool Evaporation Is Normal In Florida?

About ¼” of evaporation is normal for pools in Florida each day. However, extreme temperatures and uncovered swimming pools could lose an inch or more of water.

Wide, shallow pools lose more water than narrow, deep pools, regardless of the climate and location. Some places in Florida are more humid than others, so they don’t cause as much evaporation.

Florida swimming pools typically don’t lose more than a quarter-inch of water through evaporation. The humid climate keeps the air saturated with water, which slows the evaporation process. However, you should still use solar blankets or another form of evaporation protection to keep your pool chemicals in the water.

How Much Pool Evaporation Is Normal In Summer?

Around one to five inches of evaporation is normal in the summer each week. High temperatures can increase evaporation, especially if there’s an ongoing dry heat wave. Fill the pool with hose water and ensure the water never dips below the skimmer basket. Evaporation can send air bubbles into the plumbing if left unchecked.

Most pools lose about two inches of water a week through evaporation. However, I’ve encountered plenty of swimming pools that have lost five or more inches of water in a week.

Dry heat is the worst thing your pool has to deal with in terms of evaporation. The air is completely unsaturated, which means it can absorb plenty of water.

Summer weather provides the biggest opportunity for evaporation. It’s crucial that you protect your pool from excessive evaporation; otherwise, you’ll be in a constant struggle to fill the water, add chemicals to balance the pool’s chemistry, and maintain a comfortable water temperature.

That being said, some pools evaporate quicker than others. It’s not uncommon for swimming pools to lose several more inches during the summer than in the winter. Rainwater can fill the pool during the off-season, making it seem like the water isn’t evaporating as much, though.

Why Is My Pool Evaporating So Fast?

Your pool is evaporating so fast because it’s hot and dry outside. The heat loosens the water molecules, causing them to evaporate. You can use a solar cover, a liquid solar blanket, solar rings, or solar balls to limit the evaporation. Make sure you let the chemicals off-gas by removing the cover for a couple of hours each week.

You can slow your pool’s evaporation with these techniques:

  • Use a liquid solar blanket. Liquid solar blankets prevent evaporation and heat the swimming pool. Natural Chemistry’s Cover-Free is an excellent liquid solar blanket that creates a thin invisible layer. You can’t see, feel, or smell the chemical. It prevents up to 85% of evaporation daily.
  • Find and patch the leaks in the pool. Many people attribute the loss of water to evaporation, but they’re actually dealing with a leak. Minor leaks can increase the water loss by a couple of inches weekly. Try the test in the following section to know if you have leaks in the pool.
  • Add a solar cover to your swimming pool. Solar covers are incredibly effective. One of my favorite pool covers is the Sun2Solar Pool Blanket. It’s a 12-mil cover that prevents up to 95% of evaporation and chemical loss. Your swimming pool will stay full, saving time, energy, and money on your water bill.
Sun2Solar Blue Solar Cover

Evaporation is inevitable, even if you have all of these suggestions in play. However, it’s worth preserving the water in your pool. Not only does adding hose water dilute the chemicals, but it can also send air into the system and cause plumbing issues.

If you think you’re dealing with an abnormal amount of evaporation throughout the year, read on.

How Do I Know if My Pool Is Leaking or Evaporating?

You can know if your pool is leaking or evaporating by performing this quick test:

  1. Place a five-gallon bucket in the shallow end of the pool. Make sure the bucket doesn’t get any water in it. I suggest putting it on a step to keep the rim a few inches above the water line. Don’t let anyone get in the pool for a couple of days while performing this test for the best results.
  2. Fill the bucket with enough water to be at the same level as the pool water. For example, if the pool water on the outside of the bucket is three inches below the top of the bucket, fill the inside of the bucket up to three inches below the top. This ensures your bucket and swimming pool have the same depth and water level.
  3. Check the bucket and the swimming pool after a few days. The water level should be a couple of inches lower in both sources. If the water in the pool is lower than the water in the bucket, you know you’re dealing with a leak. If they’re the same height, you’re dealing with natural evaporation.

Pro Tip: Make sure you use a solar blanket with the bubbles facing the correct direction. If the bubbles aren’t pointing the right way, they’ll be mostly ineffective. Furthermore, you can risk damaging the solar blanket and sending small bits of plastic into the plumbing. Solar blankets are the best defense against evaporation.


  • Jonah Ryan

    Jonah has worked for several years in the swimming pool industry installing and repairing equipment, treating pools with chemicals, and fixing damaged liners. He also has plumbing and electrical experience with air conditioning, ceiling fans, boilers, and more. When he's not writing for Temperature Master, he's usually writing for his own websites, and

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