How to Find a Leak in an Above-Ground Pool

Closeup of an above-ground pool

Rep0rter / Getty Images

Project Overview
  • Working Time: 1 - 3 hrs
  • Total Time: 1 - 3 hrs
  • Skill Level: Beginner

If your watering hole’s water level is a little lower than usual, it may be a sign that you have a leak in your above-ground pool. Or you may have come outside, ready to enjoy your pool on a hot day, and heard the sound of the skimmer sucking in air. Both are signs that your pool is losing water and you have a leak.

Generally, a leak in an above-ground pool is not terrible to find. Since it is above ground you have the luxury of having the exterior and all the plumbing/mechanicals exposed.

Before You Begin

There are only a handful of locations that a leak can be coming from: any penetration locations, plumbing lines or machinery. Make note of the condition of all of these before your touch anything. Also take note of the water level as this is a telltale clue of where/what the leak could be from. If possible, for larger leaks, approximate how many days it took for the leak to become noticeable from the last time the pool was filled to a certain height.

Safety Considerations

 When finding and repairing any leak in any type of pool, there is always risk of making the leak worse and potentially loosing water or causing damage to property in the area. Before starting any work, always be aware of your surroundings and make sure to not have anything sharp on or any sharp tools loose nearby. If at any time you see water going where it should not be out of the pool or feel there is a risk of property damage, immediately stop and call a professional.

What You'll Need

Equipment / Tools

  • Teflon tape
  • pH testing liquid
  • Silicone
  • Underwater patch repair kit


  • 6-1 screwdriver (for hose clamps)
  • Caulking gun
  • Small, medium and large channel locks
  • Open ended wrench set


While the leak could be coming from a few different locations and each repair slightly different this will take you through step by step to find and repair most common types of leaks in above-ground pools.

  1. Turn the Pump Off

    Turn the pump off. This is so the water stays as still as possible to find the leak. If the water is still draining out we will be able to see it with the pH testing liquid.

  2. Observe the Water Level

    Take note of the water level. If the level is below the skimmer mouth, then we have a leak in the pool. If the water level is even with the bottom of the skimmer mouth or return fitting, it is highly probable that our leak lies somewhere with the mechanical system or penetrations. Steps 3, 4, and 5 will guide you through what to do next. If that isn't the case, you'll want to assess the liner with the help of Steps 6 and 7.

  3. Check the Penetrations for Leaking

    Inspect the exposed piping for wetness or any puddles around fittings or connection points which would indicate a leak. If all pipe and mechanicals are dry, stand on the outside of the pool looking in and, being as gentle as you can with the water, squirt a copious amount of the liquid around the frame of the return fitting and skimmer mouth. If there is a leak you will see the liquid getting sucked into the area around the fittings.

    You can fix a leak in this area fairly easily by replacing the gaskets (found at a local pool supply store) using a screw driver.

  4. Check the Pump Motor Connection

    Inspect the connection to your pump motor or hose to see if it’s wet or you have a puddle nearby. If you do, simply trace the water trail back to the suspected joint. This may bring you to a cracked hose, loose hose clamp, or threaded connection. For a cracked hose or loose hose clamp, it is better to replace them than leave them be and risk a costly repair. A pool motor is designed to be cooled with the incoming water and running it dry can cause it to burn up. If it is a cracked hose, then replace it with the same size and length hose with a hose clamp on each end.

    If the dripping (any dripping—no matter how small it is, it is not wanted) is coming from a threaded fitting, you can fix it yourself if you are comfortable doing minor mechanical work. Close off the skimmer mouth with a block off plate and turn the multiport to closed. If your return has a valve on the outside of the pool, close that as well. Drain the section in question by removing the hose out of the threaded pipe in question with channel locks. Liberally add silicone to the threads. Then rethread the hose in using channel locks being very careful not to over tighten it. Stop immediately once you feel resistance.

  5. Check the Pool Filter

    Some types of pool filters have drain plugs that can start leaking. If this is where the water is coming from, simply apply silicone to the threads and retighten in the same manner.

    In addition, most pool filters have at least one pressure gauge with a release valve. If the leak is from the release valve, try to tighten it; if it won’t tighten, stop. It must be replaced. Make a note of your filter’s make and model and bring that information with you to your local pool supply store.

    If the pressure gauge fitting is leaking, remove it with a wrench. Apply Teflon tape to the thread and reattach the gauge fitting. Pro Tip: the correct way to apply Teflon tape is to hold the gauge in your left hand and apply the tape away from you. That way, when the gauge is screwed back in, the Teflon stays on the threads and keeps itself on, instead of unwrapping itself.


    If you see water leaking out of your pump motor between the housing and the motor, call a professional. This means the spring loaded mechanism inside that keeps the water from the motor has failed and must be replaced, which requires electrically disconnecting it and taking apart the pump.

  6. Assess for Liner Rips Around Ladder and Stairs

    If the water level is below the skimmer mouth and return fitting and there are no other penetrations where you can see leaking, there is a good chance the liner has ripped. When this happens, the water usually stops leaking once it reaches the same level as the tear. The best way to find a leak in the liner is to first inspect any areas where there are ladders, stairs, or anything else rubbing on the liner floor or walls for tears or wear marks. If anything looks suspect, gently squirt the pH tester liquid near the location of the wear. If it is the source of the leak, you will see it suck in the liquid.

    Follow the instructions on the underwater patch kit for the proper repair procedure. These kits sometimes only get used once or twice during a pool’s lifetime so don’t be afraid to use a bigger piece of material than is needed. You want a piece that is big enough to properly adhere to the liner and completely cover the tear once you have surrounded the tear with glue.

  7. Check the Bottom of the Pool

    If there are no wear marks and the water level has stopped dropping somewhere between the floor of the pool and the skimmer mouth and return fittings, then it’s time to get wet! Carefully enter the pool with the pH tester kit and slowly go around the water level looking and feeling for tears. Even a small tear is something that must be patched. Once you feel that a potential tear has been identified, squirt some pH testing liquid on the tear. If it sucks it in, then you found your leak. Use the underwater patch kit to repair it.

    If your tear is on a seam of the liner, call a professional for an evaluation. Most of the time when the liner starts to rip at the seam, even if patched, the rip will travel down the seam length and get bigger, eventually ending with complete failure.

When to Call a Professional

Of course, not all pool systems are created equal and some are more complicated than others. If at any time you do not feel comfortable doing any of these steps or the leak has not stopped, call a professional. Also, as mentioned before, if your leak is coming from an area more complex (like the pump) or you find that a tear on the liner has developed at the seam please call a professional so they can assess your exact scenario and help you choose the most cost effective repair.