My Pool Is Losing Water: Is It a Leak or Just Evaporation?

Written by Steven Shipler, Texas Licensed Master Plumber and Responsible Master Plumber, Texas License #45825.

“My pool is losing water. How do I know whether it is leaking or whether the Texas heat is simply causing evaporation?”

This is one of the most common questions we receive from homeowners in Plano, Dallas, Richardson, and the surrounding Dallas–Fort Worth area.

Some swimming pool water loss is normal. Hot temperatures, direct sunlight, low humidity, wind, heated water, fountains, waterfalls, swimmers, and splash-out can all reduce the pool level.

When the pool water level keeps dropping, distinguish measuring water loss from identifying its cause:

On a mild, calm day, the water level may barely move. During very hot, dry, or windy weather, a small amount of evaporation may be expected.

A drop below a water-level mark does not by itself distinguish a leak from evaporation. Compare losses under the same conditions and investigate unexplained differences.

Compare pool loss with evaporation

A comparative bucket test measures water loss in a bucket and in the pool during the same period. Greater loss from the pool suggests loss beyond evaporation and warrants investigation. The comparison does not locate a leak.

There is no single weekly water-loss threshold that proves a leak in every pool. Weather, water temperature, water features and pool use affect observations. Rain or added water can make a test difficult to interpret.

Follow Anderson Manufacturing’s bucket-test instructions and ask a pool professional for guidance suited to your equipment and access conditions.

What Causes Normal Pool Evaporation?

Evaporation is the process of liquid water becoming water vapor and leaving the pool surface.

Several conditions can affect total pool water loss in Plano and Dallas:

• High air temperatures
• Warm pool water
• Low humidity
• Strong wind across the water surface
• Direct afternoon sunlight
• Large pool surface area
• Heated spas
• Waterfalls and fountains
• Deck jets and bubblers
• Swimming and splash-out
• An uncovered pool

Water features increase the amount of water exposed to moving air. A waterfall or fountain can therefore increase evaporation even when the plumbing system is not leaking.

Signs the Water Loss May Be More Than Evaporation

The pool should be professionally evaluated when you notice one or more of the following:

• The pool needs water several times each week
• The automatic fill valve operates constantly
• The pool loses more water than the evaporation comparison during the same period
• The loss continues during mild or calm weather
• The pool loses more water while the pump is operating
• The pool loses water even while the pump is off
• Wet ground appears near the pool or deck
• The pump draws air or repeatedly loses prime
• Air bubbles appear at the return fittings
• The water level stops at the skimmer, light, or return elevation
• Cracking appears around the skimmer or tile line
• The pool chemical balance changes because of constant refilling

Compare Water Loss With the Pump On and Off

Tell your technician whether water loss appears to vary with circulation-pump operation. Ask for guidance appropriate to your equipment before changing its schedule.

Greater Loss While the Pump Runs

This may point toward a leak in a pressurized part of the system, such as:

• A return line
• A spa return or therapy-jet line
• A waterfall or water-feature line
• A filter, heater, valve, union, or equipment fitting
• A backwash or waste line

Continued Loss While the Pump Is Off

This may point toward:

• A pool shell crack
• A leaking skimmer
• A pool light niche or conduit leak
• A main drain or suction-line problem
• A fitting below the standing water level
• An attached spa equalization issue

These patterns help guide the inspection, but they do not prove the exact cause by themselves.

Common Places Swimming Pools Leak

Why a Texas Master Plumber Should Perform the Testing

Confirming that the pool is losing water is only the beginning.

The next step requires understanding the pool’s circulation system, suction plumbing, pressurized returns, valves, pumps, fittings, equipment, underground lines, attached spa, and water features.

A single pressure drop does not always prove that an underground pipe is damaged. A result may be affected by a leaking test plug, trapped air, temperature changes, an incorrect valve position, or a problem with the test assembly.

A Master Plumber should verify the setup, isolate the suspected line, perform the test, and test again before recommending demolition.

Professional Pool Leak Testing Process

Tools Used for Pool Leak Detection

1. Professional Pressure-Test Equipment

Pressure plugs, gauges, hoses, test manifolds, and isolation fittings are used to determine whether individual pool plumbing lines hold pressure.

2. Electronic Geophone and Acoustic Equipment

Electronic listening equipment may amplify the sound of air or water escaping from a damaged underground line beneath the deck, yard, or pool structure.

3. Dye and Visual Inspection Equipment

Dye syringes, inspection lights, mirrors, cameras, plugs, and visual tools help evaluate skimmers, lights, drains, returns, cracks, and shell penetrations.

Plano, Dallas and Richardson Pool Leak Detection

Lone Star Leak Locators serves North Dallas and Collin County, including Plano.

No matter the city, the proper process is the same: confirm the loss, isolate the system, test the plumbing, verify the result, and identify the probable repair area before demolition begins.

Dallas and Plano Service Area Maps

You Receive a Written Report

Lone Star Leak Locators provides a written report documenting the testing performed and the results obtained.

After locating the leak, we provide an estimate for repair. Our team also performs repairs.

A Real Pool Leak Investigation in Murphy

A homeowner reported losing about two inches of water daily. Our investigation found two leaks at the equipment area. We repaired both and retested with no further leaks detected. Read the Murphy pool leak case study for the findings and repair outcome.

What Does Leak Detection Cost?

Detection starts at $339 and up. The final quote depends on the work required; this is a starting price, not a fixed price for every pool. Read our pool leak detection cost guide or see our North Dallas and Collin County pool leak detection service.

Regular hours are Monday–Friday, 8 a.m.–6 p.m. Emergency availability is 24/7, including weekends.

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Frequently Asked Questions