How To Fix A Leak In An Above-Ground Pool Liner

Most above-ground pools use a flexible vinyl pool liner that fits inside a metal frame. The liner material is usually a laminated PVC material that is resilient enough to "give" and conform to ground irregularities, but this flexibility also means that it is possible to puncture the liner and cause a pool leak. Fortunately, it is relatively easy DIY for you to repair a pool leak, and there is usually no need to drain the pool since the patching materials are designed to be applied underwater.

Above-ground swimming pools can develop leaks at a number of places, so it's first important to do some leak detection to determine where exactly where the water is leaking from your pool. There are several ways to determine if you're facing an actual liner leak or a leak from some other component.

Swimming pools typically lose 1/4 to 1/2 inch of water per day due to simple evaporation — and even more in climates that are very hot and dry or very windy. Also, if your pool is used daily by active swimmers, plenty of pool water can be splashed out of the pool. So, it is probably not a cause for too much concern if your pool loses an inch or two of water per day. If it's more than this, though — especially if the water loss occurs while the pool is fairly idle — it's probably a good sign that you have a liner leak.

A second strong hint that you have a liner leak is the location of the puddling water on the ground. Liner leaks — especially those in the bottom of the pool where they are most likely — can turn your yard into a soupy mess around the edges of the pool. If the leak is fairly small, you might just notice a suspicious moistness to the soil all around the pool. If the tear is substantial, you might even see bubbling water somewhere around the base of the swimming pool where water is oozing out from the bottom.

If the leak is at a hose connection or strainer joint, on the other hand, you'll likely be able to spot the leaking joint, and the wet ground is usually confined to the area immediately below the joint. Moreover, if the leak is in a water line connection, the pool will drain down to that level and then stop losing water.

There are several options for repairing leaks in a vinyl pool liner, though one solution is clearly the best. The important thing is to patch the leak fairly quickly, not only to avoid wasting water but also to minimize any damage to the liner itself. Pool liners are designed to be in constant contact with water, and they will become brittle and susceptible to cracking if the water level falls and exposes the liner to the sun for long periods. Repair options include:

• ​Waterproof patching tape:​ A variety of waterproof tapes is available, which can be used to patch small holes in a pool liner. Just cut a section of tape, round off the corner of the patch with scissors, apply it over the hole and hold it in place for a couple of minutes until it bonds securely. It's important that the liner material be thoroughly scrubbed clean before applying the tape to ensure a good bond. Patching tape should be regarded as a fairly temporary fix, as such patches will eventually fail.
• ​Peel-and-stick patches:​ Similar to waterproof tape, peel-and-stick patches come in precut sizes. After cleaning the liner surface, you peel off the backing paper, apply the patch over the hole and hold it in place until it bonds.
• ​Vinyl liner fabric with vinyl glue:​ The best option is to use genuine pool liner material and vinyl glue. With this type of patch, the vinyl glue literally melts the patch material into the pool liner itself, forming the best possible bond. You can buy the liner material and vinyl glue together as a patch kit or as separate components. For example, you may be able to buy liner material from the pool manufacturer to exactly match your liner and then buy a can of vinyl glue separately.

Of the various methods, using actual vinyl liner material with vinyl glue is the best and longest-lasting option, but don't expect any patch to be as durable as the original liner. A vinyl pool liner that begins to develop leaks on a regular basis is one that should probably be replaced within a year or two.

1. Clean the Pool

Start by scrubbing and vacuuming the bottom of the pool thoroughly to remove as much dirt, algae and discoloration as possible. Pool leaks will be easier to spot if the liner is clean.

2. Identify the Leak

Most leaks are at the bottom of the liner, but side leaks are possible if your pool gets heavy use. Kids, for example, are known to let family dogs swim in a pool, and their toenails can easily puncture the side of a vinyl pool. Sidewall leaks are usually easy to spot since the water will be visibly draining down the outside surface of the pool.

Most leaks are in the bottom of the pool liner, and there, the leak will usually appear as a dark spot or perhaps a small tear. The best way to identify these is by getting in the pool wearing swim goggles and closely inspecting the bottom of the pool. As you come across small spots, probe them carefully with a toothpick to see if there is a puncture that penetrates the liner. If so, leave the toothpick in place to mark the puncture spot.

An alternative method is to use a small squeeze bottle of food coloring dye. When you come across suspicious areas, squeeze out a small amount of dye and watch carefully to see if the dye is whisked through the hole with the flow of water. Mark the hole area so you can readily find it.

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3. Scrub the Liner

The liner must be as clean as possible to ensure the patch adheres, so use a scrubbing sponge to scour the area immediately around the hole, taking care not to exaggerate the damage. Once the area is clean, make sure the hole or tear is marked so you can find it quickly to apply the patch.

4. Prepare the Patch

Cut a piece of patch material large enough to fit over the damaged area with about 2 inches to spare in each direction. Round the edges of the patch, as squared patches are more likely to rip off over time.

Following the manufacturer's directions, spread vinyl glue over the bottom of the patch and fold it upward around the tip of your finger as you prepare to dive down and apply the patch over the hole.

5. Apply the Patch

To be successful, a patch needs to lie flat against the liner surface without air bubbles in the patching material, so this step is the most important.

Press the center of the patch directly over the hole in the liner and then smooth it outward toward the edges of the patch. Continue to press down firmly until the patch is firmly bonded. You may want to lay a heavy weight over the patch to keep it pressed in place, or you may be able to apply pressure with your foot. Follow the manufacturer's recommendations. Most suggest holding the patch in place for two minutes or so, which gives the glue time to set and bond.

6. Apply a Double Patch (Optional)

Some pool owners find good success by double-patching — applying a second vinyl patch over the first. The second patch should be at least 1 inch larger than the first patch on all sides so that the edges of the second patch are in direct contact with the pool liner. Spread vinyl glue over the entire bottom surface of the second patch so it bonds to both the pool liner and to the first patch.

If your pool liner is requiring frequent repair and is beginning to look a bit ragged with patched spots dotting the liner, now is the time to begin shopping for a new liner. It's unusual for an above-ground pool liner to last more than about 10 years, and six years is more typical.