How to Diagnose and Fix a Pool-Skimmer Leak

Written by Jeff Grundy
on Jul 06, 2010

To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.

Reviewed by
Charles Ramos, Jr.
on Dec 27, 2019

Red food coloring

Underwater pool-repair putty

Screwdriver

Red food coloring

Underwater pool-repair putty

Screwdriver

If you’re constantly topping off your swimming pool because the water levels are dropping, the issue is likely more than just the summer heat — it’s a pool-skimmer leak. Luckily for you, those leaks are easy to fix, as long as the skimmer isn’t physically damaged. Because most leaks are caused by the skimmer pulling away from the concrete, you can usually fix one of these leaks in a few simple steps.

Shut off the Pool Pump

Before you start, switch off the pump for your pool. When the pump is off, it is easier to find leaks around the skimmer box area.

Add Water, if Needed

The water level in your pool needs to be high enough so that it reaches the area where the skimmer box is located. If the water level is not high enough, add water until the level is about 1 inch higher than where the skimmer box meets the pool wall.

Remove the Skimmer Cover

Remove the skimmer cover from the skimmer area. Some skimmer-cover boxes have more screws you will need to remove before uncovering it. However, most usually have plastic snaps or handles you must simply disengage before removing the box.

Locate the Skimmer Leaks

Before repairing the leak, you should make sure the skimmer is definitely the source of it. To do so, pour a couple of drops of red food dye around the area where the skimmer is located.

You should start to notice the red food coloring flowing into the skimmer. If the dye flows into the seams around the skimmer, the skimmer is definitely the source of the leak. Take note of where along the seam of the skimmer the food dye is flowing into, as this is where you will need to make your repairs.

Apply Repair Putty

Once you have located the area along the seam where the leak is, remove a piece of underwater pool-repair putty from the tube. You can find this substance from most pool stores. Knead the putty with your fingers a few times and press it into the area along the seam of the skimmer where the leak is located.

Next, smooth out the putty with your fingers. After about 30 minutes, the putty should change to a white color. This color change indicates that the putty has cured, and you can now turn the pump back on. Replace the skimmer box covering that you removed earlier.

Diagnose Additional Leaks

If the water level in your pool continues to drop, there could be leaks in other areas. You can also use the red food coloring to test the vacuum and return fittings in your pool for additional leaks.