Is Your Pool Leaking or Just Evaporating?

Start Here: The 60-Second “Leak or Evap?” Check

Pick the closest match. Then jump to the exact section that tells you what to do next.

• I just want to know what “normal loss” looks like
• Give me the fastest at-home checks
• I’m seeing warning signs (wet spots / air bubbles / fast drop)
• Explain the bucket test (briefly) without making this page about it
• My water loss has a pattern (night only / pump on / stops at a level)
• I’m pretty sure it’s a leak — what do I do now?

What “Normal” Water Loss Can Look Like

Every pool loses water. Sun, heat, wind, humidity swings, splash-out, backwashing, and water features all remove water.
The goal isn’t “zero loss.” The goal is spotting when loss is outside normal behavior.

Normal-ish loss usually looks like this

• The drop is fairly steady and lines up with hotter or windier days.
• Loss reduces when features/heater are off and weather calms down.
• No new wet spots, no soft deck areas, no pump losing prime.

Loss that should raise your eyebrow

• You’re topping off constantly just to keep the skimmer happy.
• The drop stays high on mild, calm days with features/heater off.
• The waterline falls to a specific point and repeatedly “wants to stop” there (clue).

For Florida-specific ranges and what pushes evaporation higher in Florida backyards, use:
Florida homeowner evaporation guide.

Fast DIY Checks Before You Guess or Start Buying Stuff

1) Mark-the-waterline test

1. Bring the pool to its normal level.
2. Put a piece of tape at the waterline (tile), or mark inside the skimmer throat.
3. Run the pool normally for 24 hours.
4. Compare the new level to your mark.

2) Equipment pad walk-around

• Look for slow drips at unions/valves, pump lid, filter drain, heater loop.
• Check for wet soil that never dries around the pad.
• Listen for hissing at fittings when the system is running.

3) Feature reality check

Spa spillovers, waterfalls, deck jets, bubblers, and fountains can spike evaporation by throwing water through the air.
If you’re unsure, run an A/B day: one day normal, one day features off.

Red Flags That Point Toward a Real Leak

Evaporation is mostly “surface math.” Leaks usually come with extra clues.

• Soft spots or constantly damp soil near the pool or deck.
• Deck movement, new cracks, or hollow-sounding areas.
• Air in the system: pump losing prime, gurgling, bubbles returning.
• Autofill running constantly (or a higher water bill with no other cause).
• A waterline that falls to a point and repeatedly stabilizes there (often near a fitting).

The Bucket Test (Briefly): The Clean Separator

The bucket test isn’t the whole story. It’s just the cleanest separator:
evaporation-only vs evaporation + leak.

• The bucket can only lose water to evaporation.
• The pool loses water to evaporation too—plus any leak.
• If the pool drops more than the bucket under the same conditions, that’s leak behavior.

Two rules: autofill off during the test, and don’t change pump/heater/feature settings mid-test.

Full setup guide:
How to do a bucket test (step-by-step).

Patterns That Hint Where the Problem Is

If the pool only loses water when the pump runs

• Often points toward pressure-side plumbing, fittings, or equipment pad leaks.
• Could also be a leak that only shows under pressure (system running).

If the pool keeps dropping and then “stops” at a consistent level

• That stopping point can line up with a specific fitting: skimmer mouth, returns, lights, or a crack band.
• It’s a clue (not proof), but it helps pros diagnose faster.

If loss seems worse at night

• Night loss can still be evaporation, especially with heaters and cooler air.
• Use the bucket comparison to confirm instead of guessing.

If you want the shortest “pattern → next action” guide:
Evaporation vs splash-out vs leak.

If It’s a Leak: What to Do Next (Without Wasting Money)

If your checks and bucket comparison point to a leak, avoid random patching. Confirm the source so the repair is actually the repair.

1. Write down your observations: pump on/off difference, stopping level, wet areas, air in system.
2. Inspect the pad again for drips at unions/valves/pump lid/heater loop.
3. If loss is consistent, schedule leak detection to pinpoint the source.

FAQ — Leak vs Evaporation