Pool Leak Detection ~ Find and Fix your leaking swimming pool!

by Sean Griffin, May 23, 2009

A leak in your swimming pool can be difficult to find, especially if it not visible. Here are some hints to help locate a leak on your pool plumbing, your pool surfaces or your pool equipment.  
To help detect a leak you really need to use your detective skills. The water leaving your pool can be making its exit out of numerous connections and/or openings. There could be more than one leak.
First and foremost you should rule out evaporation (bucket test) and splash-out and backwash water. No sense in looking for a leak that does not exist. If the leak is less than 1/4" per day, it may just be evaporation, or it may be hard to locate. pool leak
The second place to visually check is at your equipment pad. Here is where several parts come together and leaks often occur. On a nice dry day look for any type of moisture. Even if there is no visible drip the escaping water could be seeping out from low spots or even beneath equipment creating a “wet-spot” on pad or surrounding area. Don’t limit checking for moisture at the equipment pad, walk around pool perimeter checking ground for abnormal moisture. Look inside skimmer throat to inspect for cracks or splits. In fact, the interface of the skimmer and the pool is one of the more common areas for leaking.
freeze plugsAnother option is to isolate equipment and plumbing (including any drain). First shut off the pump and remove any timer dogs from timeclocks. Use winterizing freeze plugs to or threaded plugs to plug off the pool skimmer, return lines, cleaner lines, etc. If water level is still dropping with all lines plugged/capped-off you can assume leak is within a light fixture, in the skimmer throat, or any connection that does not include plumbing loop. The opposite can be assumed if water stops leaking when all lines are plugged, the leak is probably in the plumbing lines or at the equipment pad.
For vinyl liners, plugging the lines in this way can be a helpful way to isolate the leak in order to “see where water level drops”. In some cases this is not practical - don't let the water drop too close to the floor - but can be very helpful. Generally vinyl liners tend to leak wherever a purposeful hole was cut; for the skimmer, the returns, even the frame around the underwater light or pool steps.
                      bubblesYou can use a dye syringe to help locate a leak anywhere inside the pool with a dye syringe around suspected areas and see if it gets sucked out of any crack or gap. Shut off the pump and allow the water to stop circulating before dye testing. A common leak is in conduit for light fixtures. Some products to help with leak in light fixture include a light cord stopper and butyl tape. Another common leak is inside your skimmer throat after years of the ground shifting they can pull away from pool. The remedy for skimmer cracks is a simple, two part resin epoxy pool putty.    
A quick way to find leaks on suction side of pump is to shut-off system and inspect for any spray that might occur due to backflow. Listen for any hissing and/or gurgling. Leaks on the suction side of pump may only occur while system is off , while pump is running it will draw air resulting in air trapped in strainer housing or filter. I recommend re-plumbing any loose/leaking connections. Leaks often occur at seals with worn or cracked o-rings. To increase the life of o-rings use a silicone based sealant/lubricant.
Underground leaks are in a category all by themselves, and are usually quite rare. After determining exactly which line does not hold pressure by “pressure testing" the plumbing, you still need to determine approximate location of problem to avoid digging up entire line. Undergroung plumbing repair can become difficult especially if it involves cutting the deck to access pipes.
American leak detection is a nationwide company that specializes in leak detection. They can save you the headache of locating a leak underground in the pipes, using specialized leak detection equipment. But first try these tips, in most cases you can find and fix the leak yourself.

For more information on swimming pool leak detection, visit our leak detection page at POOLCENTER.com. Pool leaks can be hard to find sometimes, especially when very small. If you have other pool leak detection questions, please let us know.