How To Find a Leak In Your Pool

Written by Michael Dean
March 19, 2024

swimming pool with a leak

Finding a leak in your pool is the last thing you want. While some leaks can be a quick and easy fix, others can be a huge pain that may be expensive to repair. Luckily, armed with the proper knowledge, you should be able to quickly locate a leak in your pool.

The thing about pool leaks is that they can occur practically anywhere inside and outside of the pool. The most significant challenge is often locating the leak in the first place. I will give you some strategies for finding leaks and discovering if you have a leak or if the problem is just evaporation.

Main Takeaways

  • The main way to determine if you have a leak in a pool is to fill a bucket with water and place it in the pool so that the waterline of both matches.
  • Use food coloring to detect the source of the leak in your pool.
  • The most telltale sign of a leak is if your water level drops at an unusual rate.
  • If you have a tear in your vinyl liner, you’ll need a vinyl patch kit to repair the tear. If you have a crack in a concrete pool, you’ll need to repair the pool plaster.

How to Locate the Leak in Your Pool

There are two steps in detecting a pool leak. The first is to use a bucket to determine if you have a leak or not. The second step is locating the source of the leak with food coloring.

Step One: Use a Bucket to Determine There is a Leak

The bucket test is simple and is the best way to check if there is a leak in the first place.

Supplies List

  • 5-gallon bucket
  • Duct tape

Steps to the Bucket Method

  1. Grab a 5-gallon bucket.
  2. Submerge the bucket in the water and place it on the second step of the pool (or any step where most of the bucket is submerged but not the entire thing).
  3. Fill the bucket so that the line in the water matches the waterline of the pool.
  4. Mark the waterline of the bucket using a piece of duct tape.
  5. Turn off the pool pump.
  6. Wait around 24 hours.
  7. Compare the waterlines. If the water in the bucket is higher than the pool, then there is likely a leak; if they are still the same, the pool water is going down due to evaporation.

This method is critical in eliminating the possibility that your pool’s water level is depleting due to evaporation.

Step Two: Use Food Coloring or Leak Finder Dye to Locate the Leak

Once you have determined that your pool has a leak, the best way to pinpoint the exact area where the pool is leaking is by using leak finder dye or food coloring.

Yes, you read that right! They make dye specifically for finding leaks in swimming pools. Here is my recommendation from Leakmaster.

Leakmaster Pre-Filled Dye Tester for Finding Pool/Spa Leaks

You don't have to use food coloring to find leaks these days! Leakmaster makes a good leak finder dye specifically made for pools.

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I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Supplies List

  • Food coloring or leak finder dye
  • Duct tape or waterproof tape

Steps to the Dye Method

Okay, let’s find that leak. Here are the steps to find a leak using dye:

  1. Grab some food coloring or leak finder dye.
  2. Turn the pump off to ensure the water is as still as possible.
  3. Check the areas around the pool for wetness. If you have an above ground pool, you can check the sides of the pool. If you have an inground pool, check the yard near the pool to see if there is a suspicious buildup of water. If there are unusually wet areas, there may be a leak there.
  4. Squeeze a small amount of dye near the area where you suspect the leak to be.
  5. If you are unsure of where the leak is, go around to different areas of the pool and squeeze some dye near the wall or near fittings, such as the return, drain, lights, and the mouth of the skimmer.
  6. If there is a leak, the food coloring or leak-detection dye will move toward the pool wall.
  7. Mark the spot with duct tape or waterproof tape so that you can patch the vinyl or repair the plaster.
  8. If neither of the above methods works, but you still have a strong suspicion, I recommend calling a professional pool company to check for leaks.

If you’re more of a visual learner, here’s a helpful YouTube video covering both of the strategies I explained above.

How to Tell If Your Pool Is Leaking

The most obvious sign of a leaking pool is water loss. However, other symptoms may indicate a pool leak. Watch out for the following signs.

The Water Level Goes Down

A pool leak will lead to a drop in the water level because, well… the water is leaking! 

However, pools also naturally lose water through evaporation, so if your waterline is dropping, it doesn’t always mean your pool has a leak.

Use the above methods to determine if the change in pool water levels is due to a leak or simple evaporation. Evaporation rates vary from one place to another due to differences in climate. Even in the same place, rates can vary due to water temperature, humidity, and wind.

You should know the average evaporation rate in your area by looking at current weather data. If you’re getting far more water loss than evaporation averages, then there is a high chance you’re looking at a pool leak.

You Have Cracks in Your Tiles or Falling Tiles

When a pool leaks, the surrounding ground becomes unstable due to all the excess water. As a result, the tiles surrounding the pool may crack or begin to move. Finding gaps and cracks might mean a leak has been going on for a while, and the water has seeped farther outward.

You Have Wet Spots in Your Yard

Wet areas are yet another telltale sign. Uneven grass or muddy spots near the pool may indicate a pool leak. As the water moves underground, it erodes the soil and causes the landscaping above to shift or even sink.

Your Water Bill Is Higher Than Normal

An automatic pool-filling device can hide a pool leak by ensuring the pool stays full. However, if the device gets triggered to start more frequently than usual, your water bills will rise. Higher water bills, without another explanation, could be a sign of a leak.

There Is Water Under the Equipment

Signs of severe corrosion on pipes and pumps near the pool or stagnant water (despite no recent rainfall) typically mean your pool is leaking.

Dirt or Air Passing Into The Pool Through a Pump

A leak will make it easier for air and dirt to get pulled into the pool’s plumbing. The underwater air release often comes with an inexplicable gurgling noise. It is a sure sign of a leak.

What Causes Swimming Pool Leaks?

Pools can last for decades without any major issues if you properly care for and maintain them. That said, issues can occur, and one of the most common pool problems is leaking. The three leading causes of pool leaks are structural flaws, fitting faults, and plumbing problems.

Structural Leaks

A structural leak is a leak in the pool wall itself. For your average concrete pool, this means a crack in the shell. Structural leaks come from various factors, including ground movement, subpar engineering, pressure from groundwater, shifting soil, and alternative cycles of freezing and thawing that wear on the concrete. Structural leaks are quite common if you have a vinyl pool, as the liner may tear or wear down over time.

Fitting Leaks

A fitting is anything that penetrates the pool’s shell, such as jets, skimmers, and lights. Since concrete pools are not watertight, fittings increase the chances of a leak.

When a fitting gets inserted into the pool’s walls, the builders typically plaster around it. These plastered areas are vulnerable to leaks.

Plumbing Leaks

The plumbing in a pool can be pretty fragile and must be correctly installed. These fixtures must be secure since any movement could lead to a leak in the piping or the pool shell.

Plumbing leaks are mainly from the plumbing system’s movement, which may be caused by the settling of the ground near a pipe or corrosion.

How to Fix a Leak In Your Pool

So, what do you do once you discover a leak?

Fixing Leaking Pool Pipes

Leaking pipes will often have water pooling underneath them. Luckily, as long as you are able to locate the leaking pipe (just run a pressure test), they are fairly easy to fix. For these types of leaks, you can simply plug the crack or hole with 100% silicone sealant and Teflon tape.

Fixing Leaking Pool Skimmers

Leaking pool skimmers are typically from the skimmer separating from the shell’s concrete. To be sure, submerge the skimmer by an inch or more. Turn off the pump and use the food coloring method to check if the skimmer leaks.

You can seal it with underwater repair putty from a hardware store or pool supply store. But sometimes, all the skimmer needs is for you to tighten the screws around it. If you are unable to fix the skimmer leak yourself, call a professional.

Fixing Vinyl Pool Liner Leaks

Depending on how damaged the liner is, there are a few different ways to repair a vinyl pool liner.

Small Tear in the Vinyl Liner: Use a Vinyl Patch Kit

This method applies to above ground vinyl liner pools (I also have a completely separate guide with much more depth about how to find an above ground pool liner leak). If the tear isn’t too large, a temporary solution is to apply waterproof tape to the rip. You need to use peel-and-stick patches or a vinyl patch kit for a more permanent fix, which you can get from a local hardware or pool store. I also listed my recommended option available online below.

The patch kit should come with specific instructions on how to use it. And if you do not feel comfortable, contact a pool professional to help out.

Boxer Pool Liner Repair Kit
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I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Large Tear or Many Small Tears: Replace Vinyl Liner

Using a patch kit is the best and easiest option for vinyl pools if the tear is small and there are not too many areas to patch up. However, unfortunately, for larger repairs, you may need to replace the entire vinyl liner. Read my full article on replacing a vinyl pool liner for a step-by-step walkthrough.

How to Repair a Leak in a Concrete Pool

If you have a concrete pool leak, you’ll likely need to repair the pool plaster. However, if the crack is significant, consider contacting a professional for help. Read my guide on pool plaster repair for more on this.

When to Contact a Professional

While certain pool leak fixes, such as patch kits and basic plaster repair, are pretty simple, things can get very complicated if the leak is in the plumbing or the deep end of the pool. Some pool leaks may be especially difficult to detect, so you may struggle to locate the leak in the first place.

In this case, I recommend contacting a pool professional to handle the fix. Leaks in your pool can get worse the longer you leave them, so it is best not to snooze on the problem. Some major pool leaks may require you to replace the vinyl liner entirely or do major repairs on the pool plaster, which are complicated fixes that you shouldn’t really attempt on your own unless you have a lot of experience.

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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Patch Up That Pesky Leak 

Ultimately, the most important thing to keep in mind is that pool leaks can be fixed, so you should not panic. In fact, in most cases, you can fix the issue yourself without spending too much time or money. By detecting a leak and applying the appropriate measures mentioned here, you can enjoy your pool again without worrying about your precious water leaking away.

If you need more advice on locating and fixing a leak in your pool, shoot me a message. I am more than happy to help you out!

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