How to Find a Leak in a Pool

Swimming pools here in Miami and everywhere will sometimes leak and that is one of the realities pool owners have to face. A swimming pool is really nothing more than a giant bowl filled with water. And whenever you have water in a container made of concrete or other man-made materials, leaks are one of the things that are bound to happen.

But what causes leaks and discovering the leaks is a different matter. Due to the sheer size of a swimming pool, detecting leaks is not easy. The dimensions of the pool shell and the fact that a pool’s water level is always fluctuating make it difficult. Swimming pools always lose water through evaporation, splashing, and people getting in and out of it.

So even when the pool is leaking, the pool owner may ascribe the constant fall in water levels to other causes other than a leak in the pool structure, explains But if a pool is losing water at rates far above what is normal and there have not been significant changes in weather patterns or the way the pool is used, it is right to suspect a leak. The question now is how do you find the leak?

There are two primary ways to check for leaks in a swimming pool. They are easy enough that anyone can do them and they do not require any special skills or tools. The first method will tell you if a pool is leaking, but may not be of much use in detecting the location of the leak. The second method is more specific and can help pinpoint the exact location of a leak.

Here is how to tell if your pool is leaking.

1. The Bucket Test

For this, you will need a bucket. Any bucket will do as long as it is not too small and it does not have a leak itself. The steps for doing the test are as follows:
  • Fill the bucket with pool water, up to two inches from the rim of the bucket. The reason you use pool water is to ensure that the water in the bucket and the pool have the same temperature.

  • Position the bucket inside the pool on the pool steps, with the rim of the bucket slightly above the pool level (to keep pool water from splashing into the bucket), but with the water inside the bucket level with the water in the pool. If necessary, place a heavy object inside the bucket to keep it from being swept out of place.

  • Note the water levels inside and outside the bucket with a marker or tape. The mark inside the bucket should be at the water level within the bucket and the outside mark should indicate the pool water level.

  • Leave the setup for 24 hours and check the results. If the water level in the bucket has decreased at the same rate as the water level in the pool, you do not have a leak. But if the water level fell at a higher rate in the pool than in the bucket, then you do have a leak. (If it rained during the test, you must start over.)

  • Do the test again, but this time with your pool pump off.

2. The Dye Test

For this, you need some phenyl pH reagent (if you don’t have that, use dark food coloring), goggles and snorkel (optional, but recommended). The goggles and snorkel are needed because to do this test you have to get into the pool and submerge yourself for awhile. Also, this method works best if you already have a general idea of the leak location. Here are the steps to do the test:
  • Put on your goggles and snorkel. With the dye in hand, get in the water. The dye container should be sealed so that the dye is not released into the water when you get in the pool.

  • Get as close as you can to the area where you suspect the leak is (try the skimmer first as this is the most common place to find a leak) and release the dye in bursts around the area.

  • While staying very still - so as not to disturb the water - watch if the dye gets sucked toward the suspected leak. If the dye is pulled into the wall of the pool, you have found your leak. If it remains in the water, without dispersing, there is no leak in the area.

  • Repeat with other areas of the pool, where you suspect a leak might occur.

3. Visual Spot-Check

Get in the pool (wearing goggles and snorkel) and swim around. Look for tears or separations in the pool liner or fractures in the pool plaster (for pools with tiles or concrete). Also, check if the seal or trim around the skimmer and underwater lights are intact. You may do the dye test while checking these areas.

There you have it. Quick tips on how to find a leak in a pool. However, for the safest results, it’s best to call a professional pool leak specialist. To locate the source of a leak, we use listening equipment, pressure testing, and dye tests that require special equipment and the expertise of a professional. While some issues can be fixed on the spot, some may need additional resources to properly complete the work.

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