Hello I am the GM of Leak Masters USA in Charleston SC and one of the easy way is to tell if your pool is leaking? Do you add water everyday or every two days if the the answer is yes! OK the pool is leaking so what next? Here is my easy one to three of DIY Pool leak detection for you , First step is the check the equipment look and listen for any water look at the pool pump and filter and check the back wash line also look at the site glass for water. There is a gasket in the multi-port and when it goes bad it can cause a leak.