Water Level Drops Indefinitely
If the water level continues to drop right up until the point where you need to add water to maintain the 6-12” of water in the shallow end minimum, then you need to inspect the liner again for leaks. Use the opportunity while the pool is partially empty and inspect the lower wall and floor sections of the liner up close for any damage, rips, tears or separating seams.
The corners of the pool are a common location for holes in the liner, often caused by maintenance equipment such as vacuum heads and brushes. The deep end corners are even more susceptible to holes in the liner since the liner is stretched tighter in the corners there from the weight of the water in the deep end pulling downwards. These deep end corners are obviously harder to inspect than the shallow end ones, but warrant inspection all the same.
Hydrostatic Relief Valve FailureThe most likely candidate for leak location if the water level just continues to lower seemingly indefinitely in your pool is the main drain. Inside the main drain at the bottom of the deep end is a suction port, hydrostatic relief valve and compression fitting.
The suction port is an integral part of your filtration system, and has the suction power to trap you underwater should you restrict its flow in a poorly designed system. The hydrostatic relief valve is a one way spring and pressure operated valve that allows high water table pressure from the ground equalize into your pool to eliminate or reduce the possibility of pool damage.
Being at the bottom of the swimming pool these valves are often overlooked, and can be a very difficult to detect leak since it is the last place that you look as it is the most inconvenient to inspect. A rusty spring or a small pebble preventing the check valve from closing is enough to empty your pool completely. Replacement, repair or elimination of this mechanism is generally completed during periods of renovation where the pool is empty. It is possible to hire a diver or other professional to inspect and potentially replace the hydrostatic valve underwater.
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.