How To Fix A Pool Leak: Your DIY Guide

If you want something done right, do it yourself! Read on for the ultimate DIY guide on how to fix a swimming pool leak.

Fixing a Pool Leak Quick Answers:


Do you see changes in your swimming pool’s water level? Unusual dirt or other contaminants in the water? Water gathering under the equipment or in your yard? If so, chances are you have a pool leak problem.

A small leak can rapidly spiral into more significant problems, like algae growth or equipment breakdown. And these aren’t just costly issues to fix – they can even be dangerous for swimming if they aren’t repaired right away.

But don’t panic – fixing leaks is a normal part of pool maintenance. And most swimming pool leaks are easy and inexpensive to repair yourself, as long as you act quickly. You just have to know how to find a leak in your pool and pick up a few basic supplies from your local pool or hardware store. 

In this guide, we’ll cover the best DIY fixes for the four most common types of pool leaks. That includes your pool’s pipe connections, its skimmer, the pool liner, and cracks in the concrete structure of the pool.

How to fix a leaking pool pipe connection

Have you pinpointed a leak location in the pipes near your pool pump? 

a man finding a leak in an inground swimming pool pipe

If a pipe connection is leaking, you will likely notice water pooling on the ground beneath it. To repair this kind of leak, you will need Teflon tape and a 100% silicone sealant. 

Step 1: Power down the equipment 

Step 2: Unscrew the pipe at the leaking connection.

Step 3: Spread the silicone sealant onto the male threading.  

spreading silicone sealant onto male pool pipe threading with your hands
If you don’t want sealant on your fingers we recommend wearing rubber gloves to apply the sealant.

Note also that 100% silicone sealant is not the same as silicone caulk or latex caulk. It’s essential to use 100% silicone sealant to seal leaks in pipes and allow it plenty of time to cure before you run water through the system again.

wrapping pool pipe threading with teflon tape in a clockwise direction
Pro tip: don’t apply tape to the first thread, it makes it easier to get the thread started.

Step 4: Wrap the threading with Teflon tape, circling the pipe three or four times in the opposite direction the male adapter will be turning (usually clockwise).

Step 5: Re-fasten the pipe and its fittings, but stop turning when you feel a moderate resistance. Be careful not to over-tighten, or the connection may crack. We recommend making it hand tight plus one or two turns to avoid over-tightening it. 

Most leaks don’t occur in underground pipes. However, if you think that’s where your problem lies, we recommend you call in a swimming pool leak detection professional. A detection service professional can perform a pressure test on the underground plumbing to see which pipes are leaking. They can pinpoint the exact leak location so that you won’t have to dig up your entire yard to fix a small crack or hole in the underground pipes.

How to fix a leaking pool skimmer

Leaking skimmers are another common issue, most often caused by the skimmer separating from the concrete. 

Step 1: Check the skimmer-concrete connection by first removing the outer cover on your skimmer box. 

Step 2: Ensure the skimmer is submerged by at least an inch of water before you proceed with the following steps, adding water to your pool if necessary. 

inground pool skimmer submerged by more than an inch of water
This is what the skimmer looks like with the outer cover. Make sure you remove the outer cover before you move onto the next steps.

Step 3: Turn off your pool pump and any other equipment that will disturb the water. 

Step 4: Run a simple leak detection dye test by adding a few drops of red food coloring to the water. If you notice that your skimmer has pulled away from the concrete, you’ll see dye being drawn through the leaky seam.

Step 5: Once you’ve pinpointed the leak, use an underwater repair putty – available at pool or hardware stores – to seal it. 

Step 6: First, clean the area around the seam and lightly sand it to help the pool putty bond. 

Step 7: Knead the putty and then apply it to the leaky seam, smoothing it out with your fingers. 

Step 8: When the pool putty has hardened (after about thirty minutes), you can replace the skimmer box and turn the pool pump back on.

How to fix a pool liner leak

This may sound like a big problem, but don’t fear. You shouldn’t have any trouble fixing a tear in your vinyl pool liner as long as it’s not too large, and your liner is worth repairing – i.e., it is in otherwise good shape and not too old. Initially, for a quick fix, there’s no shame in patching the hole with a strip of duct tape while you gather what you need to fix the tear permanently.

For a more permanent fix

Purchase a vinyl patch kit. They come in blue or clear and include large strips of vinyl and underwater adhesive. Most importantly, they are DIY-friendly. 

For smaller patch jobs

Opt for a pre-cut peel-and-stick patch that is made of real vinyl and typically circular so it won’t peel off easily. In this scenario, you can also use a clear, waterproof tape. This tape can be overlapped for a robust and unnoticeable patch that is cost-effective for pool care. 

All three of these methods – patch kit, peel-and-stick patch, and waterproof tape – can be used to patch a leak underwater. (They’ll also work if your pool has lost enough water that the leak is exposed.) Begin by gently cleaning the vinyl around the hole or tear using a plastic scrub sponge or non-abrasive scouring pad. Then cut the patch in a circle that is slightly larger than the area causing the leak. Next, depending on the kind of patch you are using, peel and stick the patch, or apply a generous amount of waterproof adhesive to the patch.

Adhere the patch to the liner, ensuring you have pressed out all air bubbles and hold it in place for two minutes to allow it to cure completely. Once you have completed the job, be sure to keep an eye on the patch. If it begins to lift or peel, just add more adhesive and reseal it.

How to fix a leaking crack in a concrete pool

In a concrete pool, leaks and cracks may naturally form over time in the pool wall. If you’ve noticed even a small crack or hole in the plaster, it is best to repair it right away before it grows and (inevitably) begins to leak and cause more damage.

There are two primary options for fixing this kind of leak: epoxy and polyurethane. 


Epoxy is usually available as a two-part putty. You simply knead it together and (after cleaning and roughing the surrounding area) press it into the crack. Epoxy can be applied underwater and cures very quickly. Note, however, that epoxy is not flexible. If your pool concrete has cracked due to ongoing structural instability (i.e., the ground shifting beneath it), it may crack again in the future and require maintenance.

Polyurethane Foam

Polyurethane foam. It’s sold by pool and hardware stores in DIY crack-repair kits and may involve a particular cartridge gun that helps you inject it at the right pressure. Once injected, this material expands up to 25X its original volume, filling the crack and bonding to the surrounding concrete. Polyurethane isn’t quite as durable as epoxy but is more flexible, and thus may require less maintenance.

Of course, not every leak can be fixed with a DIY approach. As always, you’ll need to evaluate the situation and make a judgment call. If there’s significant structural damage to your concrete pool, professional repair services might be necessary.

Check the Chemical Balance

Now that you know how to fix a pool leak and check for leaks, the hard part is over, but we’re not done yet! One of the main problems caused by pool leaks is chemical imbalance. This can be unsanitary or even harmful for swimmers. It can also cause metal to corrode, and grout and plaster to dissolve. In other words, maintaining a good chemical balance is key to keeping your pool clean and well maintained.

There are a few distinct ways to spot chemical imbalance. Is the water murky? Is there algae in the pool or abnormal dirtiness? Even if your pool looks crystal clear and is not showing any signs of imbalance, we still recommend testing the water as often as possible – especially after experiencing water loss or finding and fixing a leak. You should always be watching your pool’s water level and checking its pH, total alkalinity, chlorine, borate, calcium hardness, and more.

Sound like a headache? Don’t worry – Pool Calculator makes it easy. With our handy desktop and iOS and Android mobile apps, you’ll see precisely how easy it is to get in-ground swimming pools, above-ground swimming pools, or hot tubs in balance and keep them there.

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