Same drop
The result looks like evaporation for that 24-hour period.
Signature tool
Arizona Pool Evaporation Checker
Choose the closest weather station, enter the water-level drop, and compare your pool with current local ETo or your own bucket test.
Choose the nearest weather station
Click a station on the map, choose one from the list, or let your browser find the closest station. Your location stays in this browser and is not saved by Echo.
Maricopa County ALERTUniversity of Arizona AZMet
Selected station
Gilbert - Crossroads Park
Maricopa County ALERT
Station ETo is a weather-based reference estimate, not a direct measurement of your pool. A bucket test beside the pool remains the better comparison. Automated station observations are provisional and may be revised.
Enter a measured pool drop and bucket-test drop to compare results.
Official sources: Maricopa County ALERT ETo and University of Arizona AZMet. Map data: OpenStreetMap contributors.
Simple two-day check
How to do a pool bucket test
Keep it simple. The bucket shows evaporation. The pool shows evaporation plus any leak. If the pool drops farther than the bucket, that extra drop is the part we care about.
Use 24 hours for each round. Do not run one round for 24 hours and the other for 48. If it rains, someone swims, water is added, or the pool is backwashed, restart that round.
Turn off the autofill
Turn off the autofill or automatic leveler and keep it off for both rounds. Do not add water, swim, backwash, or run water features during the test.
Set the bucket and mark it
Put a clean 5-gallon bucket, preferably white, on the top step. Before it gets wet, run painter tape from inside the bucket, over the rim, and down the outside. Fill the bucket with pool water to about 1 inch from the top. Mark the bucket level on the inside tape and the pool level on the outside tape. A pencil works well on the tape; a wet marker may stop writing.
Pump on: wait 24 hours
Let the pump run its normal schedule. After 24 hours, mark the new bucket and pool levels, take a photo, and measure how far each one dropped.
Pump off: repeat for 24 hours
Reset the water levels and marks, turn the pump completely off, and repeat the same test for 24 hours. Mark, photograph, and measure both levels again.
Run the calculator above once for the pump-on round and once for the pump-off round. Enter the pool drop and bucket drop separately.
What the results tell us
Pump-on round loses more
Return-side/pressure plumbing or an operating water feature moves higher on the list. Air entering the pump can also support a suction-side concern. These patterns guide testing; they do not prove a leak location.
Pump-off round loses more
Extra loss with equipment off can make a static leak—such as the shell, fittings, skimmer, light, or gravity-fed plumbing—more worth investigating. It does not identify the exact source by itself.
Same extra loss in both rounds
The shell, skimmer, light, fittings, drains, or another static leak move higher on the list.
These results point us in a direction. They do not prove the exact leak location.
Reference guidance: City of Phoenix Smart Home Water Guide and City of Scottsdale bucket test instructions.
How to interpret the result
A bucket test differential is a diagnostic indicator, not proof of a specific leak location. Maricopa County ALERT calculates hourly ETo from local weather inputs, while AZMet reports reference ETo. The station estimate is useful for a quick weather comparison. The bucket test remains the stronger check because it sits beside your pool in the same conditions.