How to Detect a Pool Leak Before It Becomes a Bigger Problem

A backyard pool is a great source of fun, relaxation, and exercise, but it can also be the source of costly repairs if leaks go undetected. A small leak may seem harmless at first, but over time, it can lead to water loss, structural damage, and higher utility bills. The good news? Early detection is possible if you know the signs and what to look for. Here's how to catch a pool leak before it causes major trouble.

The most obvious sign of a pool leak is unexpected water loss. Pools naturally lose water to evaporation—usually around 1/4 inch per day. If your pool is losing more than that, it’s time to take a closer look. Use the “bucket test” to confirm if it’s a leak or just evaporation. Fill a bucket with pool water, place it on a step, and mark the water levels inside and outside the bucket. After 24 hours, if the pool water level has dropped more than the bucket’s, you likely have a leak.

A spike in your water bill can be a clear sign of a leak, especially if you're topping off your pool more often than usual. Even a small leak can waste hundreds of gallons of water each week. If your pool has an automatic fill system, it may be masking the symptoms by constantly refilling, so be sure to keep an eye on water usage even if the pool appears full.

A leaking pool can cause saturated soil around your pool area, which may show up as soft, wet patches in your yard or unexplained puddles. Over time, this excess moisture can erode surrounding concrete, decking, or landscaping. In more advanced cases, leaks can affect your pool’s foundation or plumbing. Pay attention to shifting ground or cracks forming around the pool or deck.

Pool leaks aren’t always in the shell—they often occur in the equipment. Check your pump, filter, heater, and plumbing connections for dripping water or visible cracks. Leaks in the equipment area are typically easier and cheaper to fix, so it’s important to inspect them regularly. Turn your equipment on and off to see if leaks only happen during certain times.

If you suspect a leak in a specific area, like a crack in the pool wall, near the skimmer, or around fittings, you can use pool dye to check. With the pool pump off and the water still, squeeze a small amount of dye near the suspected area. If there's a leak, the dye will be pulled toward it. This test is useful for pinpointing hard-to-see leak spots.