Pool Losing Water? Leak vs Evaporation: The Bucket Test Guide

The bucket test, step by step

Fill a bucket with pool water and place it on the first or second step, weighted so it sits stable. Fill or settle it so the water level inside the bucket matches the pool level outside it. Mark both levels. Run the pool as normal for 24 hours. Then compare: if both levels fell by the same amount, the loss is evaporation. If the pool fell further, the pool is losing water somewhere.

• Use a plain bucket — no lid
• Keep the pump on its normal schedule
• Avoid the test on a day of heavy rain or pool parties
• Repeat with the pump off for 24 hours if the first test shows a leak — the comparison can hint whether the leak is pressure-side or suction-side

Why there is no single 'normal evaporation' number

Evaporation depends on temperature, sun, wind, humidity and water features. Any guide quoting one universal figure for every pool in every week is guessing. The bucket test works precisely because it measures your evaporation, in your pool's weather, on the same day.

Where pools actually leak

If the test confirms a leak, the usual suspects are: the skimmer (especially where it meets the shell), light niches and conduit, fittings and returns, cracks in the shell, the equipment pad and its valves, and the buried suction or return plumbing. A useful clue: if the water level always stabilises at the same height, the leak is probably at that height.

How professional pool leak detection proceeds

Equipment and visible fittings are inspected, suspect points are dye-tested, and plumbing lines are pressure-tested one by one. A line that will not hold pressure is leaking and can be pinpointed before any deck work is discussed. You finish with a verdict — shell, fitting, equipment or plumbing — not a shrug.

Frequently asked questions

Need help with this at your property? See Pool and Spa Leak Detection or request leak detection service.