How to Find a Leak in a Pool and Get to the Bottom of It

Find your pool leak and get it fixed so you can get back in the swim of things

Swimming pool in summer day
Photo: Caia Image / Collection Mix: Subjects / Getty Images
Swimming pool in summer day
Photo: Caia Image / Collection Mix: Subjects / Getty Images
SKILL LEVEL
Simple
COMPLETION TIME
2 hours
COST
$30 – $45
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What you'll need:
TOOLS
  • Bucket
  • Goggles
SUPPLIES
  • Duct tape
  • Dye
  • Pool putty
  • Waterproof tape

Pools are a lot of fun until you’re left wondering why your water level has dropped. Learning how to find a leak in a pool can help you assess or repair the problem before it gets worse. Like any other problem around the house, it’s best to identify and fix any issues as soon as possible. Get started right away and detect a swimming pool leak in four easy steps.

Angi Tip

A pool will lose between 1/4 to 1/2 inch of water per day from normal evaporation or usage. If you find your pool is losing more than that, contact a pool specialist who can use leak detection equipment to diagnose the issue.

Caroline Gilbert
Director, Content & Editorial, Angi

How to Find a Swimming Pool Leak

Prepping to Look for a Swimming Pool Leak
Photo: Tomasz Zajda / EyeEm / Getty Images

Looking for a pool leak might sound like a straightforward task, but you should keep some important pool safety considerations in mind. For one, avoid accidental electrocution by staying away from wet electrical wires.

Secondly, be careful not to fall into the pool while doing your inspections. Also, only dive underwater to look for the leak if you have the swimming and diving skills to do so safely. 

If you’re sure you can take all of the necessary safety precautions, familiarize yourself with the potential sources of your pool leak, which may include:

  • Accessories

  • Equipment

  • Fittings

  • Plumbing

  • Shell

  • Skimmer

  • Underwater pool lights

Another important thing to note is that you shouldn’t drain your pool when you discover a leak, even if it seems logical at first. You need water in the pool to figure out what’s going on.

In case you’re wondering if a pool has a leak at a home you’re about to buy, it’s a good idea to get a pool inspection to avoid any unwanted surprises down the road.

  1. Do a Visual Check Around the Pool

    Although not all swimming pool leaks are easily detectable by sight, a visual inspection is a good place to start. For example, you may have noticed your pool water levels are dropping more than a 1/2 inch a day.

    It can help to do a quick pool cleaning so you can see everything in and around your pool. Start by walking around your pool, pool deck, and yard. Keep an eye out for puddles of water in the grass, cracked pool tiles, and cracked concrete. You may also notice cracks in the vinyl or plaster or find that your skimmer is separating from your concrete.

    Next, turn off the power to your pool equipment at the breaker, and head to your equipment pad to check for leaks. Check the filter, valve, pump, and heater for leaks, and see if the ground is wet. Make sure there’s no trickling water when the pump is off.

    If you have a vinyl liner pool, do a thorough check of your liner. You may have a leak if you notice any sinkholes, tears, or separation between the fittings.

    Moreover, the older your liner, the more likely it is to suffer from tiny holes. It’s possible to temporarily fix holes smaller than 1 inch with a patch or sealant kit. If you feel up for the DIY job, you can patch a pool liner. But if the repair is significant, you should hire a pro to avoid future damage. The average pool liner replacement costs $2,400.

  2. Do the Bucket Test to Confirm a Leak

    If you suspect you have a leak, move forward with the bucket test. The bucket test helps you know if you’re losing pool water due to a leak or evaporation

    Before starting, turn off your pump. Fill a bucket with pool water, and mark the water level with duct tape. Next, mark the pool’s water level with duct tape. Wait 24 to 48 hours, and then check the water levels.

    If the water level changes are similar in your bucket and your pool, you’re dealing with evaporation. However, if the water levels are significantly different—meaning you’re losing water faster than it’s evaporating—it’s likely a leak.

    You can repeat the bucket test with the pool pump running. If you notice that the water levels are lower during this second test, then you may have a leak in your plumbing or filtration system.

  3. Try the Dye Test to Locate a Leak

    Once the bucket test confirms that there’s a leak in your pool, it’s time to figure out where the leak is coming from. If you are still unsure of potential leak locations, the best places to check are seams, cracks, fittings, and the skimmer.

    You can use red, yellow, or blue pool leak detection dyes or food dyes if you have them handy in your pantry. Red is the most commonly used dye color. However, yellow dye works well in dark-colored pools, and blue dye is best for light-colored pools.

    Before you get started, turn off the pool pump and all water features. Next, prepare a syringe with the dye and slowly release a small amount next to the suspected leak location. If there’s a leak nearby, the dye will get drawn toward the location of the leak. When you find a leak, whether it’s above the water or underwater, mark it with waterproof tape. That way, you can easily come back to it when you’re ready to apply the pool putty or patch. 

    You may also need to grab your goggles and dive into your pool to find the source of the leak. If you notice your dye moving through your main drain, unscrew the grate to locate the precise location of the leak.

  4. You’ve Found the Leak—What Next?

    Generally speaking, DIY pool putty or patches are only a temporary fix. Patches may work for a year or longer if properly installed, but you’ll need to hire a professional pool repair service near you to help you with a permanent fix.

    You may be able to fix leaks in your pool fittings using silicone. Examples of possible leak locations include your underwater lights, jets, or faceplace. A temporary patch can stop a skimmer leak, but you’ll most likely need to replace the skimmer for a permanent solution. If your leak is due to plumbing problems, above ground or underground, you should skip any DIY attempts and call a pro.

DIY vs. Hiring a Pro for Pool Leak Detection

Hiring a professional to detect a pool leak costs between $100 and $1,000, with an average price tag of $300. But, it's likely you can save on those costs and find the leak in your pool on your own, as long as you can follow safety precautions. And if you’re a handy DIYer, you may even be able to fix the problem temporarily. However, you’ll eventually have to call in a pro to help you with a permanent solution.

And while you may catch yourself procrastinating on finding a long-term solution, it’s a good idea to take care of leaks as soon as possible. The cost of repairing a pool may increase as the damage worsens.

Frequently Asked Questions

If you know your pool is leaking but don’t know where, you can do the dye test. You can do this with food dye from your pantry or a special pool detection dye that you can buy at a pool supply store. Otherwise, you can call a professional pool company to help fix the problem.

While pool leaks can happen in many different areas, the most common spots where pool leaks happen include the pool liner (especially for vinyl-lined pools), drain, pump, filters, and pool skimmer. The most costly types of leaks are usually structural ones requiring a more complex repair or those in the underground plumbing system.

Yes, you can use food coloring to find a pool leak. Alternatively, you can use pool detection dyes that are usually non-toxic and biodegradable. Depending on how much food dye you have on hand, it may be more cost-effective to use pool dyes.

The dye test is one of the best swimming pool leak detection tools because the dyes are heavier than water. By observing where the dye gets sucked in, you can find the location of your leak.

You can find a leak in an inground pool by doing a visual check, the bucket test, and a dye test. Keep in mind that skimmers are usually the culprit for inground pool leaks. However, if you cannot detect the leak location after running the tests, it’s a good idea to call in a professional pool repair service.

If you’re wondering how to find a leak in an above ground pool, the process is the same as it is for an inground pool. Note that the vinyl liner in above ground pools is fairly thin, so sharp objects easily puncture it. Additionally, the liner can wear down after constant exposure to pool chemicals, especially when chlorine levels are higher than they should be. For these reasons, small holes in the vinyl liner often cause leaks, but you can easily detect them with the dye test.

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