Is my pool leaking or just evaporating?
Use a bucket test to compare the pool with water exposed to the same sun, wind, humidity, and temperature. If the pool level drops more than the bucket level, the difference points toward a leak rather than evaporation alone.
Turn off autofill, mark both levels, and keep the bucket stable on a pool step. A second comparison with the pump on versus off can help separate plumbing and equipment leaks from shell, liner, skimmer, or fitting leaks.
Bucket test points to a real leak?
Share the test result and where the water seems to stop. We review the request for one matched local pool-repair pro when coverage is available.
How to interpret the water-loss test
Pool and bucket drop equally
No repairHow to tellBoth water lines fall by about the same amount over the same test period
The fixTreat evaporation as the leading explanation and continue monitoring after weather changes
Pool drops more than bucket
$100–$1,000 leak detectionHow to tellThe outside pool mark falls measurably farther than the water inside the bucket
The fixInspect exposed equipment and repeat a pump-on/pump-off comparison before professional detection
Loss increases with pump running
Diagnosis first; repair variesHow to tellWater level falls faster during normal circulation
The fixCheck equipment discharge and isolate pressure-side return lines
Loss continues with pump off
$100 patch to $1,500+ access workHow to tellWater falls during a quiet no-circulation period and may stabilize near a fitting or opening
The fixDye-test likely static openings and evaluate suction plumbing if the pattern supports it
Autofill or overflow hides the pattern
$0 test; valve repair often $100–$500How to tellWater bill rises or fill valve runs, but the pool level appears constant
The fixDisable autofill temporarily, confirm overflow drainage, and measure actual loss
How to run a useful bucket test
- Turn off the pool autofill and choose a 24-hour period without swimming, backwashing, or heavy rain.
- Place a bucket on a pool step, add water so the inside level is near the pool level, and mark both levels separately.
- Keep the bucket stable and compare the two drops after the same period. The pool losing more than the bucket is the important difference.
- Photograph the marks and repeat under pump-on or pump-off conditions if you need a clearer pattern for the technician.
Unlock the hiring checklist
Use this before you call a pool repair, so you know what to ask and what to avoid.
Call a pro when…
- The pool consistently drops more than the bucket
- The water level falls below the skimmer or toward a specific fitting
- Water loss changes when the pump runs
- Wet soil, deck movement, air bubbles, or equipment leaks appear
- You need line pressure testing, diving, or electronic location
Repair or replace?
A positive bucket test tells you a leak exists; it does not tell you which component should be replaced. Locate the failure first. Patch or repair isolated liner, fitting, seal, crack, or pipe failures. Replace only when the affected component is cracked, broadly deteriorated, obsolete, or repeatedly failing.
Bucket test points to a real leak?
Share the test result and where the water seems to stop. We review the request for one matched local pool-repair pro when coverage is available.
Related questions
How much pool evaporation is normal?
It varies substantially with heat, wind, humidity, water temperature, surface area, and whether the pool is covered. A side-by-side bucket comparison is more useful than a single universal inches-per-week rule.
Should the pump be on during a bucket test?
Start with normal operating conditions. If the pool loses more than the bucket, repeat comparable periods with the pump on and off. The change can help locate which part of the system needs testing.
Can rain ruin a pool leak test?
Heavy or uneven rainfall can make the marks difficult to interpret. Restart the comparison during a stable period without swimming, backwashing, or water additions.
Sources and methodology
Ranges are planning estimates, not quotes. We compare published cost data with manufacturer troubleshooting guidance and separate diagnosis from repair.