Reasons Why Your Pool Is Losing Water

Do you find yourself refilling your pool a little too often? Sometimes it can seem like your pool water is vanishing into thin air, and sometimes, it is. However, there are several reasons your pool might be losing water, and to keep all that liquid in, you’ll have to identify where your pool water is going. 

Here are the most common causes of pools losing water:

  1. The water from your pool is evaporating.
  2. Natural water loss from using your pool.
  3. Your pool has a leak in the lining.
  4. Your pool has an equipment leak.

So, let’s dive deeper into why your pool may be losing water. Additionally, I will give you potential fixes to some of the above causes of pool water loss.

1. The Water From Your Pool Is Evaporating

The number one natural cause of pool water loss is evaporation. However, evaporation is not always the reason for missing pool water, so you’ll need to do some detective work to determine the actual cause. That way, once you know why it’s happening, you’ll be able to fix the issue. 

So, let’s work together and identify if evaporation is the cause of your pool’s water loss. To test if evaporation is the culprit, first, we need to learn more about the average water loss from evaporation. Then, we need to measure your pool’s water loss.


What’s a Normal Amount of Water for Your Pool To Lose From Evaporation?

A normal amount of water for your pool to lose from evaporation is about 0.2 inches (0.5 cm) every day. Therefore, your pool should lose approximately 1.4 inches (3.56 cm) every week.

However, keep in mind evaporation rates vary based on weather, so your evaporation rate may be slightly off of 1.4 inches (3.56 cm) a week.

How Do I Know My Water Loss Is From Evaporation?

You can know that your water loss is from evaporation by using the bucket test or checking your pool water levels every week. If your pool loses around 1.4 inches (3.56 cm) weekly, it’s likely due to evaporation. 

There are two reliable methods to determine whether your pool water loss is from evaporation or a leak. The first is called the bucket test and is best for in-ground pools. The second test is to measure your water level directly. The second method is easier for above-ground pools.

How To Measure Your Pool’s Evaporation Rate with the Bucket Test

To accurately indicate the cause of your pool water loss with the bucket test, follow these simple steps:

  1. Gather your supplies. To check if your water is evaporating or leaking, you’ll need a bucket and a marker.
  2. Fill your bucket. Use your pool water to fill your bucket, leaving about an inch of space at the top.
  3. Partially submerge your bucket in your pool. Place your full bucket inside the pool until it is floating in your pool’s water. If your pool has stairs, this is the best location to place your bucket. You can set your bucket on your pool’s ladder for above-ground pools.
  4. Mark your water levels. With your marker, mark the water level inside and outside your bucket.
  5. Wait 24 to 48 hours. Allow your experiment to sit undisturbed for 24 to 48 hours. Do not use your pool during this waiting period. Water splashing out from regular pool use will interfere with your results.
  6. Check the water levels. After you’ve given the water time to evaporate, you can analyze your results. If the water level decreases equally in the bucket and your pool, your water loss is due to evaporation. If your pool lost more water than your bucket, you likely have a leak on your hands.

The bucket test is my favorite method to detect whether you’re losing water from evaporation or a leak. I prefer the bucket test because your bucket acts as a controlled variable for the amount of evaporation that should occur.

Since evaporation rates vary daily, the bucket test gives you the most accurate results. However, if you have an above-ground pool, you may struggle to find a decent position to keep your bucket. In this case, use the measurement test.

Detecting Evaporation Rate with the Measurement Test

Follow these simple steps to measure your above-ground pool’s evaporation rate with the measurement test:

  1. Gather your supplies. You’ll need a tape measure or ruler, a pen, and paper for the measurement test.
  2. Measure your pool water level. Using your tape measure or ruler, measure the distance between the upper edge of your pool wall to the top of your pool’s water level.
  3. Mark your measurement and date on paper. Be sure to mark the height and date on a piece of paper. Store this paper somewhere secure since we’ll need it again later.
  4. Repeat steps 2 and 3 after one week. Wait one week, then measure your pool’s water level using the same method. To ensure accurate results, measure at the same part of the pool you did for your first measurement.
  5. Compare your results to the average evaporation rate. You should now have a week’s worth of evaporation data. If the amount of evaporation is similar to the average evaporation rate of 1.4 inches (3.5 cm), your pool’s water loss is due to evaporation. Your pool probably leaks if you’ve lost significantly more than the average evaporation rate.

How Do I Stop My Pool Water From Evaporating?

You can’t completely stop your pool water from evaporating. However, there is a solution to reduce your pool’s water evaporation. Liquid solar covers create a barrier over your pool water. The fluid solar cover barrier traps heat and, in turn, reduces evaporation.

How Effective Are Liquid Solar Covers?

Liquid solar covers are incredibly effective, and they can reduce evaporation by 15 – 40 percent. An average-sized pool will lose approximately 40,000 gallons (151416.47 liters) of water annually due to evaporation. 

Therefore, liquid solar covers will save you between 6,000 and 16,000 gallons (22712.47 to 60566.59 liters) of water annually.

According to Pioneer Family Pools, liquid solar covers are one of the most effective tools to fight evaporation. Liquid solar covers help retain your pool’s heat as a cherry on top. Liquid solar covers are not effective enough to replace your pool heater, but they will insulate in some heat, keeping your pool warmer for longer.

Not bad, huh? If that 15 – 40 percent reduction in evaporation, paired with keeping your pool warmer, is enticing, let me recommend a liquid solar cover for you!

What Liquid Solar Cover Should I Get for My Pool?

The best liquid solar cover for your pool is an Intex pool cover. The size will depend on your pool’s size. It’s essential to get a liquid solar cover that fits your pool snugly since you’ll still suffer from water loss if you get a pool cover that leaves any of your pool water exposed.

I recommend getting an Intex Pool Solar Liquid Cover. I’ll leave a few links to different sized covers here:

2. Natural Water Loss From Using Your Pool

Your pool will lose water from regular pool use. Water naturally splashes over the edge as you use your pool, slowly releasing the water back onto your environment.

Evaporation combined with water splashing over the edge is the most common pair of pool water loss.

Unfortunately, there is no way to combat the natural water loss caused by using your pool. If you have kids who splash each other or regularly perform flawless belly-flops, these could accelerate the natural water loss.

You could limit the heavy splashing activities in your pool, but that’s no fun. This natural water loss from splashing is an essential part of pool ownership.

3. Your Pool Has a Leak in the Lining

If you didn’t detect abnormal evaporation rates from your pool, you might have a leak in your pool lining.

How To Find a Leak in Your Pool Lining

Follow these simple steps to find the leak in your pool lining:

  1. Gather your supplies. To detect a leak in your pool lining, you’ll need goggles and pool dye. If you’ve never purchased pool dye, a small container with a syringe, like Leakmaster’s Leak Locating Pool Dye (available on Amazon), is ideal.
  2. Calm your pool water. You need a calm pool to detect a leak. Switch off your pool’s pump, and give your pool water time to settle.
  3. Check for tiny bubbles. If your pool lining leaks, small bubbles will rise to the surface near the location of your leak. Look carefully around the perimeter of your pool for any bubbles.
  4. Inspect closer. You can inspect closer when you’ve detected the approximate leak location by identifying bubbles. Get in the pool, and use your hands and eyes to check the suspected leak location.
  5. Use pool dye if needed. If the leak is large enough, you may be able to detect the leak without pool dye. However, more minor leaks can be tough to identify with your hands and eyes. Use pool dye if you can’t find the leak with your hands and eyes. Slowly drop pool dye near your pool’s liner at the suspected leak location. Pool dye will naturally collect around your liner leak.
  6. Repeat the process. Pools can have multiple leaks in the lining. Therefore, you may need to repeat the above process around the entire perimeter of your pool.

Great! We’ve found the leak. I know what you’re thinking – how do I fix it? Let’s go through the steps together!

How To Fix a Pool Lining Leak

Follow these easy steps to patch a pool lining leak:

  1. Gather your supplies. To patch your leak, you need to pick up a Pool Above Heavy Duty Blue Vinyl Patch Kit (available on Amazon). A pool patching kit comes with glue and patching material. You may also need to grab a pair of scissors if trimming is required.
  2. Cut the patching material. Some kits like the one linked above have pre-shaped patches. If your kit has pre-shaped patches, you can skip this step. If you got a kit with uncut patching material, you’d need to trim it yourself. Use scissors to cut the patching material, leaving it larger than the leak you’re covering. An additional tip is to make your patch rounded. Corners on your patch can cause it to peel off prematurely.
  3. Place glue in the center of your patch. Place a dab of glue in the center of your patch. After placing the adhesive, fold your patch in half to smooth out the glue. Keep the patch folded until you’re ready to put it on the leak.
  4. Place the patch over your leak. Cover the tear or hole with the patch and hold it against the lining for 1 to 3 minutes.
  5. Leave the patch undisturbed for 24 hours. Give your patch 24 hours to make sure your patch has time to adhere to your pool lining fully.

4. Your Pool Has an Equipment Leak

If you’ve run the test and found you’re losing water at an above-average pace, you may have an equipment leak causing your loss of water.

How Do I Detect a Pool Equipment Leak?

You can detect a pool equipment leak by running either the bucket test or measurement test with your filter turned on, then again with your filter off. If your pool only leaks with the equipment turned on, you probably have an equipment-related leak.

What Causes a Pool Equipment Leak?

The causes of a pool equipment leak are usually broken seals, pool motor malfunctions, and your pool pump’s low flow rate. Anyone or a combination of these problems could cause a pool leak.

How Do I Fix an Equipment Leak?

To fix an equipment leak, it is best to call in a professional. There are many potential causes for an equipment leak, and identifying your issue can be challenging if you don’t have experience working with pool equipment leaks. 

Final Thoughts

If one of the above tips helped solve your pool’s water loss, I’m happy to have helped! I hope you have many sunny days lounging by your pool in the future.

If you still haven’t found the cause of your water loss, it’s time to call a professional. Pools are more complex than they seem, and sometimes you won’t be able to solve the problem on your own.

Call a local pool professional, and explain you suspect a pool leak but can’t identify it. Pool professionals will have the experience required to detect the cause of your pool losing water.


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