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Checking For Leaks In Swimming Pools

Does it seem like everytime you go out for swim, the water level in your pool has gone down a bit? While it is normal for some water to evaporate, if the water level is lower than it was an hour ago, there's a good chance you've got a leak.

Leak or No Leak?
To determine whether it is a leak or just evaporation that you're noticing, fill a large bucket two-thirds of the way with pool water. Next, mark off the waterline inside the bucket as well as the waterline of the pool. Then, making sure it is fastened or secured to something so that it doesn't tip over (and thereby ruin your experiment), allow the bucket to float in the pool.

Now don't use the swimming pool for about a day before you go and check the water level of both the pool and the bucket. If both the bucket and the pool have lost the same amount of water, then it is safe to say that evaporation is the reason behind your decreasing water levels. If it is only the water level of the pool that has gone down, then, unforutnately, you've most likely got a leak.

Since the multiport valve gasket is the most common culprit behind a water leak, you'll want to check your backwash pipeline when you suspect a leak. Check the pipe while the circulation system is running; if you see a trickle of water coming from the pipe, then it's a safe bet you have a leak.

No Ifs, Ands or Buts About It
If you know you have a leak, you need to find out where it is. Try this: measure how much water is lost over twenty-four hours, keeping the circulation system running. Do it again, but this time turn the circulation system off. You'll know that the leak is on the pressure side of the circulation system if the leak slows down or even completely stops when the circulation is shut off.

However, if turning off the circulation system only makes the leak worse, then you can suspect that there is a problem with the suction side of the system. When it makes no difference as to whether the system is running or not, it's likely the leak is somewhere in the pool shell.

What to Do
If your leak is on the pressure side of the circulation system, check that water is not getting behind the liner (assuming you use a liner) at the return-inlet fittings. A damaged gasket can cause water to sometimes get behind the liner.

There is also a good chance that there is a leak somewhere along the pipework. If this is the case, you should contact your local swimming pool contractor or dealer and have them pressure test the system.

If the leak is somewhere in the shell, turn off the circulation system and let the water level fall until it rests at a stagnate level. The leak should be level with the water line. If the water level cuts across a fitting or an underwater light unit, carefully check the areas around it. If the pool has a vinyl liner, then you will need to look for tiny holes in the liner.

Hammer If you have more questions regarding a leaky swimming pool, visit our Pools forum and talk to others about your DIY project!