5 Common Causes Of Pool Leaks

Even though you put a lot of effort into maintaining your pool, it will eventually need repairs. As each season passes, your pool gets subjected to harsh temperatures, extreme weather, and lots of use from the family. Because of this, it’s unavoidable that your pool may start to leak and need repairs. If you find yourself adding more than a quarter-inch of water per day or more than two inches of water per week, you may have a leak. In order to protect your pool, it’s important to know what the 5 common causes of pool leaks are.

5 Common Causes Of Pool Leaks

Typically, pool leaks can be formed by one or more of the following issues:
  • Mechanical Issues
  • Structural Damage
  • Plumbing
  • Broken Pipes
  • Loose or Broken Fittings

Let’s dive into each issue so you can better understand the source of pool leaks. If you notice any of these problems with your own pool, make sure to call a professional leak detection company right away!

Mechanical Issues

If you have an automatic fill device on your swimming pool, a drop in your pool’s water level may not be apparent. However, high water bills and a relentless fluctuating chemical imbalance can lead to an expensive “green pool” problem of excess algae growth, which can be an indicator of a leak problem.

If you have a vinyl liner pool, your pool skimmer may be where your leak is. Fortunately, it’s fairly easy to find and fix. The most obvious sign that your skimmer is leaking is that the water will drop to the bottom of the skimmer, and the leak stops. To test this, either turn the pump off or close the skimmer valves and run the pump on the drain only.

On our list of the 5 common causes of pool leaks, one that may be considered a pool owner’s worst fear is a leak in the skimmer pipe. Ripping up your pool deck and replacing the pipe is, fortunately, very rare. Signs of this being the case include:
  • Your pool is leaking more when the pump is off (because when your pump is on, it’s under a vacuum)
  • Seeing air come into the pump basket.

Related Topic: 10 Scary Facts About Pool Leaks 


Structural Damage

Structure leaks due to structural damage can happen anywhere in your pool. If you can see a crack in your concrete or fiberglass pool, then this would be the perfect place to investigate if you are losing water. Oftentimes, cracks in your pool start out small and are generally only cosmetic in nature. However, we recommend getting these cracks repaired right away. The longer you wait to repair them, the worse they get. This can lead to larger structural problems, excess water loss, and expensive repair bills! You'll need a pool leak detection expert to come and take a look at your inground pool.

Additionally, it’s common for leaks to happen around fixtures such as lights and returns. Investigate these areas by using the dye test. You can correct this by filling the opening of the conduit in the back of the socket with putty or other caulking agents appropriate for your pool construction material. If you aren’t sure how to fix the leak or don’t have the right equipment, call a professional leak detection company to handle the job.

Related Topic: How To Find A Leak In A Pool 


Swimming PoolUnderground leaks can be caused by corrosion or movements in the ground, damaging your underground plumbing or possibly puncturing the floor of your pool. If you suspect a leak in your pool’s plumbing, contact Leak Science right away. Finding a leak underground and under the decking requires expert help with specialized sonar equipment. Additionally, the longer you wait to fix the leak, the more expensive the damage and water loss becomes.

Leak Science is the only pool leak detection company that can fix and find your leak, and completely restore your pool to its original condition like nothing ever happened. We will replace any flagstone or concrete that we had to remove, leaving your pool looking like new! This means you won’t have to worry about hiring an additional contractor after we’re gone.

Read more about Leak Science here! 

Broken Pipes

Number 4 on our list of 5 common causes of pool leaks is broken pipes. Your pool’s plumbing system is complex, which unfortunately means that leaks can spring up in a variety of locations throughout the piping. This can include…

Return Pipes

When the pool and the pool return pipes settle in the ground at different rates, this almost always results in a leak where the return meets the pool wall. This type of leak is a very common leak location.

The Main Drain

The main drain is one of the hardest and most complicated factors for finding leaks in pools. Since you should not completely drain an inground pool, it is very difficult to inspect the main drain without proper training or equipment. Main drains can leak around the fixture itself as well as through the suction pipe that connects to them. Additionally, the main drain can develop leaks in the hydrostatic relief valve. This is often caused when rust or a rock obstructs the valve from closing properly.

Skimmer Pipe

Unfortunately, the underside of a pool skimmer connection point is hard to get to. Concrete pool skimmers are usually encased in concrete on all sides, making the connection point that much harder to get to without high-tech equipment and trained ears.

This is why it’s so important to hire a professional leak detection company. The various tests for the multiple reasons for leaks can be costly, all while you’re losing water and increasing your water bill. At Leak Science, we use professional sonar equipment and our 10+ years of industry knowledge to quickly and efficiently identify the source of your leak.


Leaks in equalizer pipes are one of the most likely suspects in older swimming pools. The equalizer line in the pool is a non-pressurized pipe that connects from the main drain to the underside of the skimmer. Because it is usually found in older swimming pools, it is often left out of major renovations. Call your trusted leak detection company right away if you suspect you have a pool leak.

Loose or Broken Fittings

While breaks, cracks, or collapses in the pipe can happen anywhere, they are most likely to be where joint connections have been made. This is very common in both pools and spas and can be fixed easily if the location is easy as well.

Related Topic: Pros and Cons of Hiring A Leak Detection Company 


How do I know if my pool is leaking?

Leaks are frustrating to deal with on your own. Sometimes they are obvious and easily spotted. Other times, they may build up slowly over time, leaving you with expensive water bills and costly repairs. Thankfully, there are some signs you can look for to know if your pool has sprung a leak.
  • Changes in water level
  • Wet spots in your yard
  • Unusually high water bills
  • Cracks in your pool surface or pool deck
  • Loose, cracked, or shifting pool tiles
  • Algae growth in the pool
  • Standing water under pool equipment
  • Corroding pipes

If any of these signs sound familiar, contact us right away! We’re happy to help locate and resolve your leak so you can get back to enjoying your pool.

Pool Leaks: The 5 Most Common Causes 

Swimming pools offer much-needed relief from summertime heat and an opportunity to have fun with your friends and family. But if you own a pool, you know how much maintenance they require. In addition to keeping them clean, it’s important to inspect them for leaks. The earlier you detect signs of water levels dropping and damage, the better!

Leaks can happen anywhere in your pool and at any time. You’ll want to catch and repair leaks as quickly as possible. Leaks waste your money and worsen over time, causing increasing damage and compromising the structural integrity of your pool. Watch for any signs of water damage and early signs of a leak, which could be water level loss. If you are adding more water than you normally do from water loss from water evaporation or splashing, or notice an increase in your water bill, get your pool inspected by a professional leak detection company as soon as possible.

Contact Leak Science For Pool Leak Detection & Repair Services

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