Water Level Leak Test

Fixing a leak in your swimming pool is a process of gathering information and identifying specific areas of your pool prone to leaks. For each piece of knowledge you acquire from the testing that you are doing you are taking a small step towards isolating the exact problem.

leaking pool liner

The information will also allow you to eliminate less likely leak points from your search. You will not often interpret data from any one test and be able to say exactly where the problem exists. You may however be able to determine where the problem is likely NOT to be from any one test. With the process of elimination in mind, let’s look at some more tests that you can do to identify where (and where not) your pool is leaking.






How To Do The Water Level Test

Let your pool continue to leak until the water level stabilizes and stops receding. The level that the water drains to will be a huge indication of where the leak is located. Water levels don’t lie.

It is safe to temporarily lower the water level in your vinyl liner swimming pool so long as you leave between six inches to one foot of water covering the floor in the shallow end. Concrete pools can be drained as well but should not be left drained for long periods of time. By letting your pool water level drop you can often find the origin of the leak source.



If the water level goes down to the wall returns height and then seems to slow or stop there, you likely have a hole in the return line. Wherever the water line is when it stops receding, be sure to check the circumference of the pool for small holes, tears or punctures in the liner. If you are able to conduct this test on your swimming pool, whatever the result, the findings will help to further diagnose your water loss problem.


Protect Your Pool Pump

Please note that during this test it may be necessary to shut down your circulation system so as to not burn out your pool pump when the water level drops below the skimmer mouth.

If you have a mechanical installation that allows you to isolate the main drain and skimmer suction lines and close off the skimmer, you can continue to run your pool through this test. Never drop the water level in your pool lower than 6-12” of water covering the shallow end, and avoid prolonged periods where the water level is dropped this low, especially with older liners.

Continue to the section on evaluating the results of the water level test



The menu on the right is a chronological step by step process to determine where a swimming pool is leaking. This website is written as a readthrough technical assistance guide for locating leaks. When you believe you have identified where the pool is leaking you need to go to our sister website to see pictures and learn more about the actual swimming pool leak repair process.