How to Find That Pesky Leak in Your Swimming Pool


The discovery of a leak can be a real headache for any pool owner. Even if you’re aware that you’ve sprung one, pool leak detection can be an even bigger headache!

Across a large pool who can find the smallest crack at first glance? Leaks can occur anywhere in your pool, including inside the plumbing itself.

Searching one out can feel like finding a needle in a haystack. Yet, a pool leak needs finding and fixing if you want to keep swimming.

An undiagnosed leak in the plumbing can cause major problems in your yard too. This may even lead to sinkholes. Usually, these aren’t the giant type but any sinkhole is bad news.

Pool leak detection will help you identify where that leak is, so you can get it patched up and avoid these problems.

This is a much bigger process than just walking around looking for a drip! It starts with figuring out if a leak is to blame for your symptoms. Then trying to deduce where the leak is by its cause.

Pools don’t tend to begin leaking by themselves. To make pool leak detection easier on yourself, you can narrow down the suspected leaking areas through a few tests.

The first step is to diagnose your pool.

The Symptoms of Pool Leaks

Pool Leak Detection

Before you embark on pool leak detection, you should make sure that you actually do have a leak! Misdiagnosing a different problem is only going to waste valuable swimming time.

Using the right pool maintenance team can help cut down on the hours spent looking and testing leaks. They have more exact methods for picking these things up early.

If your pool is displaying these tell-tale signs, you might need to look for a leak:

  • Losing Water – Most pools lose a bit of water through splashing, evaporation, and general use. However, if you’re losing more than 1/2 an inch each day, this is definitely a bad sign. Although if your pool has been filled with splashing children then this might account for it too!
  • High Water Bills – If you’re using more water than normal when keeping your pool filled, this is a sign you’ve got a leak. A big increase in your bills might indicate that you need to do some pool leak detection.
  • Tiles and Pool Deck Damage – If you’re losing tiles or the deck is cracking, this is a sign that something ain’t quite right.
  • Worrying Noises – Gurgling sounds are a great audio indicator of a problem.
  • Soggy Soil  – This is a clear sign of a leak in your plumbing lines.

If you’re experiencing these symptoms, then you need to get that pesky hole fixed!

The Bucket Test for Pool Leak Detection

Pool Leak Detection
Note: Small dog is not necessary for the test.

If you have some of these symptoms but you’re not quite sure if it is a leak, then you can make sure by using the bucket test.

The bucket test is simple but can accurately diagnose a leak. All you’ll need is a large bucket and a marker or duct tape. This is how you do it:

  1. Fill a large bucket with water most of the way up. Mark the full water level on the bucket using either your marker or duct tape.
  2. Place the bucket inside your pool. Ensure that the bucket’s water level aligned with that of your pool.
  3. Stop the flow of water to your pool by shutting off the recirculating pump and any auto-fill machinery.
  4. Wait for twenty-four hours.

You can clearly see in the bucket how much water has evaporated since you started the test. If your pool has lost more water than the bucket has, it is leaking water.

Repeating this test will help if the first round leaves things ambiguous.

Narrowing Down The Suspects

There is quite a bit you can do to make leak detection easier on yourself. Through circumstantial evidence, you can narrow down your search quite a bit.

Not every pool leak is going to leave a lot of clues, but it can save you a lot of time if you look out for these indicators of your leak’s location:

The Water Level

If your pool stops leaking when the water hits a certain level then this should make it clear that your leak is above that position.

Leaking More With The Pump Running

If your pool is leaking more when your pump is running, then the leak is likely a pressure plumbing leak. However, if your pool is leaking more when the pump is not running then it could be a suction plumbing leak.

Is Your Pool Leaking Constantly?

If none of these tests give you any clues and your pool is constantly leaking then you need to take a good look at the shell of it.

Wet Spots on The Ground

You should test your yard for wet spots that may be scattered around. This indicates where you might have a leak in your pipes.

Using the Bucket Test for Pool Pump Leak Detection

The bucket test detailed above can be useful for determining the location of your leak as well as confirming that you have a leak.

Repeat this test with the pump on or off to give a clearer picture of if your pump is to blame.

Test for More Exact Pool Leak Detection

Pool Leak Detection

Those techniques are going to help you determine the vague location of your pool’s leak. However, they won’t give you an exact location.

Once you’ve gotten a better idea of where to start pool leak detecting, you can start running this test to find the exact spot.

This requires quite a bit more equipment than the bucket test! You’re going to need goggles, a snorkel, and some leak finder dye. if you don’t have that dye, food colouring will work too.

  1. Fill the pool to above the leaking level – Ensure the water in your pool is high enough that it is leaking water.
  2. Go to where the leak is likely to be – Now that you’ve narrowed down your search area, you can head over to it. Be very careful not to disturb the water as you’re doing this.
  3. Add in the dye or food colouring – Drop this into the water close to the wall. If the ink begins to siphon off towards a spot in the wall, then it is being pulled in by the leak.

Of course for this to work, your pool has to be clean enough that you can actually see the dye!

Pool Leak Detection for a Lowdown Leak

If your leak is near or at the bottom of your pool, this dye test is going to be a bit more complicated. Since you won’t be able to see where the dye is headed, you will need to be under the water.

The key thing when doing this pool leak detection test low down is to move as little as possible. You need to keep the water undisturbed so the dye will flow towards the leak rather than just getting spread out among the water.

With goggles, you should be able to see where the dye is headed. With the snorkel, you can remain down there for long enough to stop the water becoming too disturbed.

Repeat the steps from the test, but do this at the best of your pool once the water has settled down.

Pool Leak Detection

Pool Leak Detection for Underground Plumbing

If you need to find a leak in your pipes, there are some simple methods you can use.

One way is to individually pump and plug every line to your pool. If the leak continues as nothing has happened, then you can rest easy that the leak is not located in your lines.

If the leak stops after the plugging, you need to figure out which line is to blame. Pool leak detection for individual lines can be done by unplugging each one. Do this methodically, one at a time.

Once the leak begins again, you should know which line is responsible. A pressure test on that line will then show you the correct location.

What To Do After Detecting a Leak

With these methods, you should have figured out where your pool’s leak is! However, pool leak detection is really just the start! You might now know that you have a leak, but you still need to fix it which can get quite expensive.

If your pool’s leak is in the liner or concrete, you’re going to need to try to patch it up. Underground leaks are going to be a bit of a harder job.

If you’re feeling up to the task, you can attempt this yourself. However, your pool’s entire plumbing is a bit of an expensive thing to risk as a DIY project. It could really go wrong if not handled correctly.

When the time comes to fix a leak, calling in a specialist is often the safest course of action. Pool maintenance teams are trained in finding and fixing pool leaks. This is a lot easier than trying to sit perfectly still underwater until the water stops moving, all while holding a bottle of dye.

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