Pool Leak Bucket Test: Step-by-Step (and How to Read the Results)

What the bucket test proves (in one sentence)

It compares evaporation (water loss from a bucket exposed to the same weather) to your pool’s water loss over the same time period.

If the pool drops more than the bucket, you likely have leak behavior. If they drop the same, evaporation (or normal use) is more likely.

Supplies you need

• 1 bucket (5-gallon is perfect)
• 1 marker (Sharpie) or painter’s tape
• A small rock/brick (optional) to keep the bucket from floating
• Your phone camera (optional, but helpful)

Time needed: 10 minutes to set up, then re-check in ~24 hours (or 48 hours for clearer signal).

Bucket test: step-by-step (do it exactly like this)

Step 1 — Pick a “normal” day

Choose a 24-hour window where you can avoid big variables: no big pool party, no major backwash, no draining, and ideally no heavy rain.

Step 2 — Put the bucket in the pool (important)

Place the bucket on a step or shallow ledge so the bucket is sitting in the water and exposed to the same air conditions as the pool.

Why this matters: A bucket sitting outside the pool doesn’t experience the same water temperature and wind exposure as the pool surface.

Step 3 — Fill the bucket to match the pool level

Fill the bucket with pool water until the water inside the bucket is close to the pool’s water level outside the bucket.

Step 4 — Mark TWO waterlines

• Mark #1 (bucket level): Use a marker or tape on the inside of the bucket at the waterline.
• Mark #2 (pool level): Mark the pool waterline on the tile/skimmer face with tape or take a clear photo reference.

Step 5 — Decide pump ON vs OFF (and keep it consistent)

Pick one setup and keep it the same the entire test:

• Option A (common): Run your pump on its normal schedule.
• Option B (stronger isolation): Turn the pump OFF for the full test window.

Tip: If you suspect a plumbing leak, doing a second run with the pump OFF can help confirm it.

Step 6 — Wait ~24 hours (or 48 hours)

After 24 hours, check both marks. If the difference is small and hard to read, run it for 48 hours for a clearer signal.

How to read the bucket test results

Result 1: Pool dropped MORE than the bucket

Meaning: leak behavior is likely. The pool is losing water faster than evaporation alone.

What it often points to next: You’ll want to figure out whether the loss tracks the pump (plumbing) or happens even when the pump is off (structure/waterline).

Result 2: Pool and bucket dropped the SAME (or almost the same)

Meaning: evaporation is the main cause, or your water loss is from normal use (splash-out, kids, spa spillover, autofill settings).

Next move: Check for “hidden” water adds/removals (autofill, overflow drain, backwash, rain).

Result 3: Pool dropped WAY more than the bucket (fast loss)

Meaning: treat it as urgent. Fast loss can lead to pump damage, soil washout, or bigger repair costs.

Next move: Stop guessing and schedule detection so a pro can isolate the source quickly.

Common mistakes that ruin the bucket test

1) Putting the bucket outside the pool

Outdoor buckets don’t match the pool’s thermal mass and wind exposure. Always do it in the pool.

2) Changing pump settings mid-test

If the pump schedule changes during the test, you can accidentally “create” a difference that isn’t real. Keep it consistent.

3) Forgetting autofill / overflow behavior

If an autofill is running, it can hide a leak by adding water constantly. If you can safely do so, turn it off during the test.

4) Rain or heavy splash-out

Heavy rain can distort readings. If it rains, re-run the test on a calmer day for clean results.

5) Not marking both levels clearly

Use tape or take a photo so your “before” and “after” are obvious.

Next steps (based on what you got)

If pool > bucket (leak likely)

• Run a second test with the pump OFF for 24 hours.
• Watch for a stop level (does it stop at the same height?).
• Use a dye test near the suspected level if you have a clear target.

Best move: Schedule detection and share your bucket test result + pump on/off behavior.

If pool ≈ bucket (evaporation likely)

• Confirm spa spillover isn’t running longer than you think.
• Check autofill and overflow drains.
• Re-run for 48 hours if you want stronger confirmation.

If pool dropped fast (urgent)

• Protect your equipment (don’t run the pump if the water level is too low).
• Schedule detection before the problem expands.

Ready to schedule?