Why Does My Pool Keep Losing Water?

Pools lose water through evaporation, splash-out, backwashing, and cleaning. They can also lose water through a leak in the shell, plumbing, equipment, or automatic-fill system. The key is to compare the pool with water exposed to the same weather instead of relying on a guessed “normal” amount.

Why evaporation changes

Evaporation increases with warm water, low humidity, wind, long waterfall operation, and a large difference between water and nighttime air temperature. Chino and Inland Empire heat can make water loss noticeable, especially during dry or windy periods. A cover can reduce evaporation when used safely and correctly.

Perform a 24-hour bucket test

Turn off the automatic fill. Fill a bucket with pool water and place it on a pool step so several inches are submerged. Mark the water level inside the bucket and the pool level outside. Avoid swimming, backwashing, or adding water. After 24 hours in clear weather, compare both marks.

If the pool and bucket drop about the same amount, evaporation is the likely explanation. If the pool drops more than the bucket, a leak is more likely. Rain or heavy splash-out invalidates the comparison.

Signs of a possible leak

- The automatic fill runs frequently or continuously.

- Water repeatedly stops at the same tile, light, skimmer, or fitting level.

- The equipment pad stays wet when the system runs.

- Air appears in the pump basket or returns.

- The pool loses substantially more water with the pump on or off.

- Decking or soil near the pool stays unusually damp or settles.

Do not let the water fall below the safe skimmer level; a pump can lose prime and run dry. Do not drain the pool to search for a leak because draining can damage the shell and equipment.

When to call for leak detection

A positive bucket test confirms abnormal loss but does not identify the location. Leak detection may involve dye testing, pressure testing plumbing lines, acoustic equipment, and inspection of lights, skimmers, drains, returns, and structural penetrations.

If your Chino-area pool keeps needing water, contact Superior Pool Pro for practical next steps. Regular equipment observations are also part of weekly pool service.

FAQ

Can an autofill hide a leak? Yes. It can maintain the visible level while increasing water use.

Does a wet equipment pad always mean a pool leak? Not always. Condensation, rain, irrigation, or a loose connection can mimic a leak, but persistent water should be investigated.

Source: American Leak Detection bucket-test procedure. Updated September 9, 2026.