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Inground Pool Light Leak Repair

In the quest for a pristine and well-maintained inground pool, the issue of light leaks can pose a significant challenge. Inground swimming pool lights are prone to leakage from the conduit, which is the pipe that carries the light cord from the lamp to the junction box. A pool light conduit is ¾” or 1” gray PVC pipe, running under the deck. The pipe can allow water entry because it lacks sealing where it connects to the light niche. In some cases, water in the conduit may freeze solid, cracking the conduit and start to leak out from the pool. In other cases, the conduit can be cracked during deck placement, or from shifting soils or sliding slabs.

Is The Pool Light Leaking?

a pool light can leak

The way to determine a pool light leak is by continuing to operate the pool on main drain only (close or plug the skimmers), and allowing the water level to drop. If the water level seems to stabilize at the level of the light, or more precisely, just a few inches below the top of the light – you may have a conduit leak. To be certain, you can add a few inches of water and shut off the pump, plugging the skimmers, returns and the main drain pipes, and any other pool plumbing lines, with expansion plugs.

If an inground gunite pool continues to leak with all the lines plugged tightly and the pump shut off – that means that there is a leak in the pool shell or the pool light. Vinyl liner pools have to rule out leaks in the liner, or anywhere the liner was purposely cut; such as the steps, skimmer, return, drain and pool light.

For more advanced leak detection, Anderson Manufacturing makes a Pool Light Tester, allowing you to seal up against the pool wall, and add leak testing dye to watch if it gets sucked out of the conduit.

How Low Can You Go?

If the water level continues to drop below the halfway point of the light, you may have a conduit leak. However, there is also some other leak somewhere else. A conduit leak will only leak down to the port on the upper back of the light niche, where the conduit connects.

Pool Light Niche Leaking?

Pool light niches rarely leak. It’s extremely rare for a pool light to be leaking through the shell of the light niche, or around the light niche. 99% of the time a pool light is leaking, water is running out through the light conduit. Vinyl pools, however, have the light niche gasket sealed to the pool wall, which has more leak potential around the niche.

Is There Water Inside?

If there is water inside the lens of the pool light, which you can usually see from on-deck, that doesn’t mean that the light is leaking, it does mean that the lamp gasket has failed, letting water leak inside and surround the bulb. Correct this potentially hazardous situation, but note that it is not the source of the pool leak.

Fixing a Pool Light Conduit Leak

water inside pool light

Relax, we won’t be digging up the broken light conduit, there are a few ways to seal up the light conduit from inside the pool, where it connects to the back of the light niche.

Silicone: With the water level at mid-light or lower, squirt silicone rubber up into the conduit, and around where the light cord enters the port. Clean the areas beforehand, to improve the bond and seal.

Pool Putty: Mix up half of the epoxy/resin Pool Putty, and pack it around the (cleaned up) light cord and connection port. Make a cone of putty that seals up against the niche, cord, and port. Fill the pool back up, and allow the light to remain on deck for 24 hours, to allow the putty to dry. Carefully reinstall the light to avoid disturbance to the putty.

Light Cord Stopper: For the most permanent solution to a pool light conduit leak, seal up the hole in the light niche with a Light Cord Stopper. Made in two sizes, to fit 3/4" or 1" hole, with a hole running through it to allow the light cord to pass through. Just push it in place firmly to keep water from entering the conduit.

In The Swim makes every effort to provide accurate recommendations based upon current ANSI/APSP/ICC-5 2011 (R2022) standards, but codes and regulations change, and In The Swim assumes no liability for any omissions or errors in this article or the outcome of any project. You must always exercise reasonable caution, carefully read the label on all products, follow all product directions, follow any current codes and regulations that may apply, and consult with a licensed professional if in doubt about any procedures. In The Swim assumes no legal responsibility for your reliance or interpretation of the data contained herein, and makes no representations or warranties of any kind concerning the quality, safety, or suitability of the information, whether express or implied, including, without limitation, any implied warranties of merchantability or fitness for a particular purpose.