In Arizona, pools typically lose between 1/4 and 1/2 inch of water per day to evaporation during the summer months. Water loss greater than that — especially loss that continues into cooler weather — usually indicates a leak. The most reliable way to tell the difference at home is the bucket test, which compares your pool’s water loss to evaporation under the same conditions.
If you’ve noticed your pool dropping faster than it used to, this guide will help you figure out whether you’re dealing with normal Arizona evaporation or an actual leak that needs attention.
How Much Water Does an Arizona Pool Lose to Evaporation?
Arizona’s climate is uniquely hard on pools. Low humidity, intense sun, high summer temperatures, and constant wind all accelerate evaporation far beyond what pool owners in other states experience.
Typical evaporation rates for Arizona pools:
- Summer (May–September): 1/4 to 1/2 inch per day
- Spring and fall: 1/8 to 1/4 inch per day
- Winter: 1/16 to 1/8 inch per day
A standard residential pool can lose anywhere from 2 to 4 inches of water per week during peak summer — entirely from evaporation, with no leak involved. This is why so many Arizona homeowners assume they have a leak when they actually don’t, and why others ignore real leaks for months thinking it’s just the heat.
Wind and water features make a big difference too. A pool with a running waterfall, fountain, or spillover spa can lose noticeably more water simply because more surface area is exposed to the air.
The Bucket Test: How to Tell If Your Pool Is Leaking
The bucket test is the gold standard DIY method for distinguishing a leak from evaporation. It works because it exposes a bucket of water to the same temperature, sun, and wind conditions as your pool — so whatever evaporates from the bucket should match what evaporates from the pool. Any extra water loss from the pool points to a leak.
Watch: How to Run a Pool Bucket Test (Video)
In this 5-minute video, Brandon from LeakLab sets up a bucket test in a real backyard and walks through the key steps below, including the second round most guides skip.
Video: Brandon from LeakLab walks through the pool bucket test (4:57).
Here’s how to do it:
- Turn off the auto-fill. The shutoff valve is usually on the side of the house, connected to a vacuum breaker. After closing it, push down on the float to confirm no more water comes out. Auto-fill will mask a leak, so don’t skip this.
- Turn off all pool equipment. The simplest way is to switch off the pool breakers at the panel. Automation systems often have a service mode, but turning off the breakers guarantees nothing kicks on during the test.
- Fill a 5-gallon bucket with pool water. Fill it fairly high, leaving about an inch of space at the top.
- Place the bucket on the second step of your pool. This keeps the bucket water at roughly the same temperature as the pool. Weight it down with a rock if needed so it doesn’t float away.
- Mark the water level inside the bucket and outside on the pool side. Use a permanent marker or tape.
- Wait 24 hours, then compare the two marks. If the pool dropped a lot more than the bucket, you have a leak.
- If both dropped the same, run the test again with the equipment on. Some cracked pipes only leak when they’re pressurized with water moving through them. Re-mark both levels, turn the breakers back on, let the equipment run normally, and check again after another 24 hours.
Run the test for two or three days in a row if results are borderline. A difference of more than 1/4 inch over 24 hours is a strong indicator of a leak.
Other Signs Your Pool Is Leaking (Not Evaporating)
The bucket test is the most reliable single method, but several other signs point to a leak rather than evaporation:
- Soggy, sinking, or unusually green areas around the pool deck or yard. Underground plumbing leaks often surface as wet spots in the landscape.
- Cracks in the pool deck or settling pavers. Water escaping under the deck can erode the soil and cause structural shifting.
- Air bubbles coming from return jets when the pump is running. This often indicates a leak on the suction side of the plumbing.
- The pool loses water only when the pump is on, or only when it’s off. Loss with the pump on suggests a pressure-side leak. Loss with the pump off suggests a structural leak or suction-side issue.
- Water loss continues at the same rate during cooler months. Evaporation slows dramatically in winter. A leak does not.
- Your water bill has jumped without explanation. Auto-fill systems silently top off leaking pools, and the cost shows up on the utility bill.
- The chemical balance is harder to maintain than usual. Constantly adding fresh water dilutes chemicals and throws off pH, chlorine, and stabilizer levels.
If you’re seeing two or more of these alongside faster-than-normal water loss, it’s almost certainly a leak.
When to Call a Professional
If the bucket test confirms a leak, or if you’re seeing the warning signs above, professional leak detection is the right next step. DIY troubleshooting beyond the bucket test gets unreliable fast — most leaks happen in plumbing buried under decking or in the pool shell itself, and they can’t be located without specialized equipment.
A professional leak detection service uses methods like:
- Pressure testing to isolate which plumbing line is leaking
- Electronic and acoustic listening equipment to pinpoint leaks under concrete and decking
- Sonar and dye testing to confirm the exact leak location before any repair work begins
This non-invasive approach matters because it prevents the most expensive part of pool leak repair: tearing up perfectly good decking, plaster, or landscaping while searching for a leak. A proper detection service tells the repair team exactly where to dig, and nowhere else.
Frequently Asked Questions
How much water loss is normal for an Arizona pool?
Most Arizona pools lose 1/4 to 1/2 inch per day in summer, and 1/16 to 1/8 inch per day in winter. Anything significantly above those ranges, especially when the weather is mild, is likely a leak.
Can a pool lose water from splashing alone?
Yes, but rarely enough to mistake for a leak. Heavy use, especially with kids or a busy spa, can account for an extra 1/4 to 1/2 inch over the course of a day. If your pool is consistently losing water on days with no swimmers, splashing isn’t the cause.
Should I do the bucket test with the pump on or off?
Both, in that order. Start with all pool equipment off for 24 hours, which checks for structural and suction-side leaks. If the pool and bucket drop the same amount, run a second 24-hour test with the equipment on. Some cracked pipes only leak under pressure, so the second round catches pressure-side plumbing leaks the first one can miss.
How fast can a pool leak get worse?
A small leak can stay small for months, but pressure-side plumbing leaks tend to worsen quickly because pressurized water erodes surrounding soil and pipe joints. Structural leaks in the shell can also expand as water continues to work through cracks. Catching a leak early almost always saves money.
Is it worth getting professional leak detection?
Yes, especially in Arizona. Undetected leaks lead to higher water bills, soil erosion under decking, and damage to the pool structure itself. Professional detection identifies the exact source before any repair work begins, which avoids unnecessary demolition and gets the problem fixed correctly the first time.
Think You Have a Leak?
If the bucket test confirmed a leak — or if the signs are pointing that direction — LeakLab specializes in non-invasive pool, spa, and water feature leak detection across Mesa and the greater Phoenix area. We use pressure testing, electronic detection, and dye verification to find leaks accurately without tearing up your property.
Call LeakLab at (602) 622-8390 or contact us online to schedule an inspection.
