Turn off power before you touch anything

The first step is always to cut power to the light fixture. Locate your pool's circuit breaker panel — usually mounted on the house or in a utility area — and switch off the breaker labeled for the pool light. If the label is unclear, turn off the main pool breaker instead. Wait a few minutes to let any residual charge dissipate.

Do not skip this step. Pool lights run on 120 or 240 volts depending on your pool's age and size. Working on a live circuit can cause serious injury or death. If you are not confident identifying the right breaker, call a licensed electrician before you proceed.

Once the breaker is off, test the light switch to confirm no power reaches the fixture. Flip the switch on — the light should not turn on. This confirms the circuit is dead.

Key Takeaways

  • Always turn off the breaker and test the light switch before touching any part of the fixture.
  • Most in-ground pool lights are sealed units that you remove and replace as a whole, not bulbs you change like a household lamp.
  • The fixture sits in a niche (a recessed pocket) in the pool wall, and you will need to drain the niche or the entire pool depending on the design.
  • Replacement lights cost between $300 and $800 installed, and the job usually takes one to three hours once power is off.
  • If water is leaking from the niche or the light will not turn on even after you replace it, call a pool technician — the problem may be in the wiring or the niche seal.

Drain the niche or the pool

In-ground pool lights sit in a niche — a recessed pocket built into the pool wall. Before you can remove the light, you need to drain the water around it so you can work safely and see what you are doing.

Some niches have a drain plug at the bottom. If yours does, open it and let the water drain into the pool. If there is no drain plug, you will need to lower the pool water level below the niche opening. Use a submersible pump or your pool's main drain valve to lower the level. This usually takes a few hours depending on how much water you need to remove.

Once the niche is empty or the water is below the light opening, dry the area with towels. You want the niche and the fixture completely dry before you start removing bolts or connectors.

Remove the old light fixture

The light fixture is held in place by a trim ring — a metal or plastic ring that screws or bolts to the niche. Look for bolts around the edge of the trim ring, usually four to six of them. Use a wrench or socket set to loosen and remove each bolt. Keep them in a safe place — you will reuse them for the new light.

Once the bolts are out, gently pull the fixture toward you. It will slide out of the niche. Be careful not to yank the electrical cord — you need to disconnect it safely.

Inside the niche, you will see the electrical connection. This is usually a junction box with wire connectors (often called wire nuts) holding the light's wires to the pool's main circuit. Unscrew each wire nut by turning it counterclockwise, then gently separate the wires. Take a photo of the wire arrangement before you disconnect anything — you will need to match it when you install the new light.

Inspect the niche and seal

With the old light out, look inside the niche for cracks, corrosion, or water damage. The niche should be dry and the concrete or fiberglass should be intact. If you see cracks or the niche is wet even after you drained it, there is a leak in the niche itself. This is a job for a pool technician — they can reseal or repair the niche before you install a new light.

Check the rubber gasket or seal that sits between the fixture and the niche opening. If it is cracked, hardened, or missing, you will need a replacement gasket. Most new pool lights come with a gasket, but if yours does not, buy one that matches your fixture model.

Install the new light fixture

Before you slide the new fixture into the niche, install the gasket around the back of the trim ring. The gasket should sit in a groove or channel on the ring. Press it firmly so it is seated all the way around.

Slide the new fixture into the niche, aligning the bolt holes on the trim ring with the holes in the niche. The fixture should sit flush against the niche opening with no gaps. If it does not fit smoothly, stop and check that the gasket is not bunched up or misaligned.

Once the fixture is in place, reconnect the electrical wires. Match the wire colors to your photo: black to black, white to white, and bare copper to bare copper. Twist each pair of wires together, then screw a wire nut onto the connection. Tug gently on each wire nut to make sure it is tight and will not come loose.

Now install the bolts through the trim ring and into the niche. Tighten them evenly in a crisscross pattern (like tightening a car wheel) so the ring pulls in straight and does not bind. Do not over-tighten — snug is enough.

Refill and test

Close the niche drain plug if there is one. If you lowered the pool water level, use your pump or fill valve to bring it back up to normal. Wait until the water level is above the light opening and the niche is sealed again.

Once the pool is refilled, go back to the breaker panel and switch the pool light breaker back on. Go to the pool and flip the light switch. The new light should turn on. If it does not, turn the breaker off again and check that all wire connections are tight and matched correctly.

Look at the niche opening from underwater if you can — you should see light coming from the fixture and no water leaking around the trim ring. If water is leaking, turn off the breaker, drain the niche again, and check that the gasket is seated properly and the bolts are tight.

When to call a professional

Call a licensed pool technician if the light still will not turn on after you have checked all the wire connections. The problem may be in the circuit itself, the junction box, or a tripped breaker that keeps shutting off. These are electrical issues that require a licensed electrician.

Also call a technician if water is leaking from the niche even after you have tightened the bolts and reseated the gasket. A persistent leak usually means the niche itself is cracked or the seal is damaged below the surface. Trying to fix this yourself can damage the pool structure.

If you are not comfortable working with electrical connections or you have never done this job before, there is no shame in hiring someone. A pool technician can replace the light in an hour or two and will may provide the work.

Frequently Asked Questions

Can I replace just the bulb instead of the whole fixture?

Most modern in-ground pool lights are sealed units — you cannot open them to replace the bulb. The entire fixture is designed to be removed and replaced as one piece. Older pools sometimes have fixtures with replaceable bulbs, but even those are rare. Check your fixture manual or ask a pool technician if you are unsure.

How long does it take to replace a pool light?

Once the breaker is off and the niche is drained, the actual removal and installation usually takes one to three hours. If you need to lower the pool water level first, add several more hours for draining and refilling. A professional can often do it faster because they have the right tools and have done it many times.

What if I do not know which breaker controls the pool light?

Turn off the main pool breaker or the breaker labeled "pool" or "spa." If you still are not sure, turn off the main house breaker — this is the safest option. You can always turn other circuits back on once you have confirmed the pool light is off. Never guess with electrical work.

Do I need to drain the entire pool to replace the light?

Not usually. Most niches have a drain plug or you can lower the water level just below the light opening. You only need to drain the entire pool if the niche is above the waterline or if there is a structural problem with the pool itself. A pool technician can tell you what is needed for your specific setup.

What size light do I need to buy?

The new light must match the niche size and the voltage of your pool's circuit. Check your old fixture or the niche itself for the size — common sizes are 8 inches and 10 inches in diameter. Check your breaker panel or the old fixture for the voltage — 120V or 240V. Bring these measurements to the pool supply store and they can match you with the right replacement.