By Roger Wakefield, Licensed Master Plumber · Published November 2, 2026
Quick answer: How does pool leak detection work? It starts by proving the pool is leaking and not just evaporating, with a simple bucket test. Then the pro splits the pool from its plumbing by running the test again with the pump on and off, checks the equipment, and only then pinpoints the leak with listening equipment, so nothing gets dug up or torn out on a guess.
In this video, Roger Wakefield walks through leak detection step by step, breaking a water system into smaller pieces before he looks for the leak. A pool is found the same way. Read on for how pros find a pool leak.
Is your pool leaking or just evaporating?
Start here, because evaporation is normal. The U.S. Environmental Protection Agency (EPA) says in its WaterSense pool water efficiency guide that evaporation is one of the leading causes of water loss in residential pools.
The EPA estimates that, depending on climate, an uncovered 500-square-foot pool could lose between 12,000 and 31,000 gallons of water a year to evaporation, and even more if it is heated. Temperature, humidity and wind all change how fast a pool evaporates.
How much water loss means a pool leak?
The EPA gives a rule of thumb: if a pool is losing more than 2 inches of water per week, or 3 inches in hot, dry areas with high evaporation, it is likely leaking.
What are the signs of a pool leak?
Water loss is the big one, but the EPA and local water utilities list other clues to look for:
- Wet spots around the pool.
- Air bubbles in the water return line or in the pump strainer.
- Visible leaks or wet spots at the pool equipment.
- White, crusty mineral deposits on the pipes, which the City of Scottsdale says can signal a slow leak.
- An automatic fill that keeps topping the pool off.
How do you do a bucket test for a pool leak?
The bucket test compares the pool’s water loss to a bucket of water sitting in the same sun and wind. These are the EPA’s steps:
- Pick a day without rain or heavy wind. Shut down all pool systems, including the filter, cleaners and automatic fill, and close the pool for 24 hours.
- Fill a 2.5- to 5-gallon bucket to about 1 inch from the top and set it on a step or bench in the pool, with at least two-thirds of the bucket under water.
- Mark the water level inside the bucket and the level of the pool.
- Wait 24 hours, then measure both again.
If the pool lost more water than the bucket, the pool may have a leak. If both dropped the same amount, it is evaporation.
How do pros tell a structure leak from a plumbing leak?
They isolate it, the same way Roger separates the yard from the house before he looks for a water line leak. The City of Scottsdale tells pool owners to run the bucket test once with the equipment running and once with it off.
If more water is lost with the pump running, the plumbing is probably the cause. If the loss is the same either way, the leak is more likely in the pool itself. LeakPro explains the same isolate-first idea in how pros isolate and locate a leak.
Where do pool leaks usually hide?
The EPA says leaks can be found in the pool liner, the pump seal, the pool piping, the pool-to-pipe connection, the pool edges and the pipe joints.
The City of Scottsdale says most pool leaks are found in the pool equipment, so pros run the equipment and look it over for visible leaks and wet spots before they go looking anywhere else.
Can an automatic fill hide a pool leak?
Yes, because it quietly replaces the water a leak loses. The EPA recommends shutting the automatic fill off for 24 hours once every three months to test for leaks, and warns that automatic fill valves can sometimes malfunction and send water to the pool’s overflow drain.
The EPA also says installing a water meter can help a pool owner watch water use and spot potential leaks. LeakPro’s guide to finding water leaks with your water meter shows how to read one.
How do pros pinpoint a pool leak?
With listening equipment, after the leak has been narrowed down. LeakPro says its water leak detection equipment helps plumbers and homeowners find slab leaks, underground water-line leaks and swimming pool leaks quickly.
Pick the right tool for the surface. LeakPro’s Probe page says the Probe is for water lines buried in soil and yards, not for slabs or swimming pools, and points to the Sidekick for hard surfaces. LeakPro calls the Sidekick the most sensitive tool in its line.
What does pool leak detection equipment cost?
These are the LeakPro prices leak-pro.com shows today:
- LeakPro Sidekick: $1,295
- LeakPro Probe: $1,395
- LeakPro Complete Kit: $2,995
See the full line in the LeakPro store. Plumbers who want hands-on practice can take LeakPro leak detection training, a 2-day course in Wylie, Texas, on a training slab with 12 real, live leaks.
Frequently asked questions about pool leak detection
These are the questions pool owners and plumbers ask most about finding a pool leak.
How long does a pool bucket test take?
The EPA’s version takes 24 hours with the pool closed and every system shut down. Rain or heavy wind can spoil the result, so pick a calm, dry day.
How much water does a pool lose to evaporation?
The EPA estimates an uncovered 500-square-foot pool could lose 12,000 to 31,000 gallons a year to evaporation, depending on climate. It says a solid pool cover can cut evaporation by more than 90 percent while it is in use.
Can a pool leak raise the water bill?
It can, when an automatic fill keeps replacing the lost water. The EPA says the average household’s leaks can waste more than 9,300 gallons a year. Read more on the signs of a hidden water leak.
Need help finding a pool leak?
Prove it, isolate it, then pinpoint it. Read the LeakPro FAQ, see the water leak test plumbers use on a house, or call LeakPro at 1-888-853-2577 to talk it through.
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