How To Find Leaks In Pool Liners?

Pool Liners

Have you ever wondered why water levels decrease in pools in spite of taking every possible safety measures? Water requires no big tunnel to drain; even a small hole is enough to leak.

Though you may think that since water can leak through holes and it is easy to identify the leak spot by looking at the wet area, the condition is not always the same. When it comes to pools, this is not an easy task at all.

Especially, if the leakage is in the liners, then you will sometimes end up in never identifying the leakage spot. So, how to find leaks in pool liners and how do you repair it? The answer is:

  1. Confirm that there is a leak
  2. Detect the leak.
  3. If it is doubted to reside in the pool liner, then confirm the same.
  4. Check inch by inch in a methodical manner till you find it.
  5. Repair it.
  6. If you are unsuccessful in locating it, replace the liner.

As we move forward, let’s discuss about each of it in detail.


What causes a pool liner to leak?

A pool liner can leak due to a number of reasons. A simple tear in the liner can cause your pool to leak. Other common reasons can be holes and punctures to the pool liner.

If it ages beyond 5 years, then you may not expect efficient results and its time that you replace it once it starts troubling you.

How difficult is it to find a leakage spot?

Fixing a leak is very easy. Finding it is very difficult. Inspecting for the spot is a great job that requires lot of patience. It takes lot of time and sometimes, you might end up with not detecting even a single leak.

Leaks can be anywhere in the pool and of any size. The biggest problem is when the leakage spot resides in the pool liner.

You may find by following some methodical techniques and find out if the leakage spot is in the equipment or surface or walls of the pool. But, if the leakage is in the pool liners then, you will be the luckiest to have found the leakage spot.

Again, if you found one, that doesn’t mean that, you have successfully completed your work. You may have unfound leakage spots. This means, you can never confirm that there is no leakage existing in the pool liner.

Confirm that there is a leak

Before you start searching for a leak, first you should confirm that there is a leak in the pool. You can check for the same by keeping an eye on the pool for one complete day. For this, you will need a 5 gallon size bucket, water and painter’s tape.

What should you do?

  1. Fill the 5 gallon bucket with water and set it right next to your pool so that both the bucket and the pool will expose their water to the same climatic conditions.
  2. Market the water level in your bucket with a painter’s tape. This tape should be gentle enough to not to harm your vinyl liner when used near it.
  3. Now, mark the water level in the pool with the painter’s tape.
  4. Next day, check if the water level has decreased from the point of tape mark for both the bucket and the pool.
  5. If you notice that the water level has decreased more for the pool from its marked point when compared to that of the bucket, then confirm that it is a leak.
  6. On the other hand, if you find that the difference is almost the same for both of them, then you can assure that the water level has decreased because of evaporation.

Find the leak is in which section of the pool

Now that you have invested one completed day and have come to a conclusion that there is a leak in the pool, the next job is to detect its location.

Swimming pool industry offers you a variety of tools that help you detect the leakage in a pool liner, but they are very complicated to use. Moreover, they are not affordable.

Some of the leakages detecting tools are:

  • Electrical Impulse Tools
  • Biodegradable Dyes

Unfortunately, both of them do not guarantee you to find the leakage spot. It is like an expensive effort to guess something out of nothing. First of all, biodegradable dyes may help you confirm if something is a leak spot or not, but will not help you to find where the leakage exists.

Confirm that the leak is in the liner

Check electrical section

Before you touch the liner section, it is easy to check with electrical and plumbing systems for leaks. If you find that there is moisture in the conduit lines that pass from the pool’s lighting system, then call a professional to handle the situation and repair it. You are not suggested to handle the issue as you may get shocked.

Check plumbing section

If you find that the water system of the pool is leaking, turn of the filters and check all the pipes, fittings and pump to find for moisture. If you confirm that the leak is in the filtration system and if the pump is failing to turn on, then you may seek for a professional service.

Check liner section

Have patience and wait till what level the water keeps leaking. If the water level stops decreasing at a specific point, then most probably the problem is near the point at which the water stopped draining. If the water has been leaking throughout, until it reached the pool liner then, most probably the problem is with the pool liner.

So, try to check with the liner if you can find any holes or punctures or if you can see any wear and tear. After checking all possible places, if you still end up with disappointing results, then you should replace the liner rather than further wasting your time.

Detect the leakage location in the liner

Now that you are confirmed that the leakage spot resides in the pool liner, you have narrowed your search to only the liner part.

To move forward, all that you will need is food colouring.

  1. Take care that the water level in the pool is full to confirm that the leakage point is not above the water level.
  2. Now, the only logical way to detect a leakage in pool liner is to typically swim into the pool and check inch by inch manually till you find the answer.
  3. As a first step, swim onto the floor level of the pool and touch to feel if there is anything squishy, indicating that the leak is at the bottom side of the liner.
  4. If you suspect a leak, just shoot few drops of food colour in the suspected area. If the colour draws back into the pool then, it is not a leak. Or else, you can see the colour spot in the suspected area and hence, can say that it is a leak.
  5. Continue the same by checking every inch area of the liner till you find the leakage spot.
  6. If you haven’t found even after investing many hours of great effort, then will only left with an option to replace the pool liner. On the other hand, if you found the leakage, then it is very easy to fix.

Fix the leak

Now you have achieved a great success in detecting the location of the leak by performing a tedious task, you have now entered into the final part – repair. Identify the size of the leak and see if a patch will suffice.

If the leak is too big to repair then ALAS! All your efforts to search for the leak have again gone in vain! You have no chance to repair! You can only replace the pool liner!


If you doubt that the problem is with the liner, first you need to confirm it. Then you should locate it by following specific methodical technique till you locate it. Once you find the leak, repair it if possible. If the leak is too big to repair, then replace the liner.

If you did not find the leak, but doubt that the leak resides in the liner, don’t get disappointed. By now, you know how to find leaks in pool liners. So cheer up! Move ahead and get the issue fixed!

You need to fix the leak as soon as possible or else the subsoil underneath will weaken. Contact a professional and get the work done professionally so that you may enjoy the warranty in case if the history repeats!

Bryan Mallory

My name is Bryan Mallory and I have over 25 years of experience in swimming pool, spa maintenance and repairs. With my experience and knowledge I can return your pool back to its best and keep it in peak condition.