Do this first, at home
The bucket test, done properly in Phoenix
Ten minutes of setup will tell you whether your pool is really losing water — or whether it is just a Phoenix June doing what a Phoenix June does.
Why a bucket and not a number
The bucket cancels out the weather
Every “normal” water-loss figure online is an average of conditions you are not having.
Evaporation off an open pool depends on water temperature, air temperature, humidity, wind and sun. In the Valley all five move a long way between April and August, and again between a still morning and a windy afternoon, so a fixed figure for “normal loss” cannot follow it.
A bucket of water sitting in your pool solves it without any arithmetic. The bucket is in the same water, under the same sun and wind, through the same afternoon. Whatever the weather takes out of the bucket it is taking out of the pool too, so anything the pool loses beyond the bucket is going somewhere that is not the sky.
What you need
Nothing you do not already own
- A clean bucket, straight-sided if you have one.
- A grease pencil, or painter’s tape.
- A ruler or tape measure.
- A brick or large stones, so the bucket cannot float or tip.
- A pool nobody will swim in hard while the test runs.
The method
Seven steps, and none of them optional
Turn the auto-fill off
An auto-fill replaces exactly the water you are trying to measure, so it hides the whole thing. Close its valve, and leave yourself a note to open it again afterwards.
Bring the pool to its normal level
Roughly the middle of the skimmer mouth on most Valley pools.
Stand the bucket on a step, in the pool
Fill it until the water inside is level with the pool outside, then set it on the top step with the brick inside. The rim stays above the surface — if the bucket goes under, the test is over.
Mark both levels, and note the time
Mark the water line inside the bucket and the pool level on the tile or skimmer face, and write the date and time beside them.
Leave it two or three days
One day is close enough to measurement error to argue either way. Two or three days puts real distance between the marks.
Measure down from each mark
From the bucket mark to the water inside, and the tile mark to the water outside. Two numbers is all you need.
Start again if the weather interfered
Rain, hard wind, a pool party, a backwash or anyone topping up with a hose all ruin the reading. Reset the marks rather than trust the result.
Reading the result
What the two numbers mean
| What you measured | What it means | What to do |
|---|---|---|
| Both dropped about the same | Evaporation, which the surface always does. | Nothing to chase. Turn the auto-fill back on. |
| The pool dropped further | Water is leaving by a route other than the surface. | Note the difference and which run, then call. |
| The pool dropped less | Something is adding water: a live auto-fill, rain, a hose. | Fix that and run it again. |
| Neither mark moved much | A short test, or a mild week. | Run it longer before concluding anything. |
The step most people skip
Run it once with the equipment on, then once with it off
This decides how the whole job gets approached, and you can hand us the answer before anyone arrives.
Run the test twice: one full run with the pump and any water features on their normal schedule, and one with the equipment off throughout. Then compare.
- Worse with the equipment running. The pressure side of the plumbing moves up the list: the returns and the pipework that is only under pressure while the pump runs.
- Worse with the equipment off. Attention shifts to the suction side and the shell, which hold water whether anything runs or not.
- The same either way. Structure and fittings come first: the light niche, the skimmer, the returns, the tile line and the plaster.
None of that is a diagnosis. It is a sorting exercise, and it decides whether we arrive set up to pressure-test lines or to listen and dye-trace a shell.
Send us two lines, not a paragraph
“Pool dropped half an inch more than the bucket over three days, worse with the pump running” beats a long description.
The myth worth forgetting
A quarter of an inch a day means nothing here
The most repeated rule online was not written for a Phoenix summer.
The rule says a pool losing more than a quarter of an inch a day has a leak. Scottsdale Water publishes month-by-month evaporation figures for an open pool in this climate, and worked out per day, June comes to more than a third of an inch with July barely behind. A sound Valley pool crosses that famous line every summer with nothing wrong with it.
Late spring is the sharpest part of it: hot, cloudless, windy and very dry at once. Then the monsoon arrives, humidity climbs and evaporation eases, so the pool that looked alarming in June looks untroubled in August with nothing repaired. A bucket follows that curve automatically. A fixed threshold cannot.
Evaporation figures: Scottsdale Water.
Before you call it a leak
Losses that are not leaks
Water leaves a pool for honest reasons that are not failures: a busy weekend with children in it, backwashing the filter, draining after a storm, a water feature on a windy day. Keep a one-line note during the test and run it on a quiet week, because a pool that dropped further than the bucket over a weekend six people swam in has not told you anything yet.
Either answer is useful
What to do next
If it was evaporation
Nothing on the pool needs fixing, and knowing that beats assuming it. Turn the auto-fill back on. If a bill started this, you have ruled out the biggest suspect in the yard, which makes the rest of the search much shorter — irrigation, the buried service line and the fixtures indoors. That is a high water bill question now, not a pool question.
If the pool dropped further
The loss is real and it will not stop on its own. Call or text your two numbers and whether it was worse with the equipment on or off. From there it is pressure testing, listening, dye and line tracing until the loss has an address — our pool and spa leak detection work.
Straight answers
Bucket test questions
How long does the bucket test need to run?
Two or three days for a reading you can trust. Over a single day, the difference between a sound pool and a slow leak is often smaller than you can read on a bucket.
Does the bucket really have to sit in the pool?
Yes, and it is the whole reason the test works. A bucket on the deck warms and cools differently, so it evaporates at a different rate. On a step it is in the same water temperature, sun and wind as the pool.
Can I do the same test on a spa, or a pool with no steps?
Yes to the spa, and it is often clearer because the surface is smaller — just keep the cover in the same position throughout. With no steps, anything that holds the bucket steady with its rim above the surface will do.
My pool loses about a quarter of an inch a day. Is that a leak?
In June or July, very possibly not. Scottsdale Water’s published monthly figures work out to more than a third of an inch a day in June, so that rate can be normal in high summer and quite abnormal in January. The bucket tells you which.
Where this leads
Tell us what the water is doing
Your two measurements, and whether the loss was worse with the equipment on or off. That is enough for us to tell you what is likely going on.
Text us your bucket numbers
Two measurements and whether it was worse with the pump on or off is enough for us to tell you what is likely going on.
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What customers in the Phoenix valley have written. The words are theirs, on listings we cannot edit.
“Humberto has been amazing! Prompt, professional, and patient. He has gone above and beyond, taking the time to show me how to operate the water valves and educating me so I can continue to monitor for future leaks. He identified multiple leaks and made thoughtful recommendations.”
“Beto was very professional, thorough and patient in explaining everything he was doing and why. It was an excellent and well worth it experience, and this is saying something for an architect who had a hundred questions!”
“The owner and operator of this company is everything a contractor should be. On time, honest, competent, reachable, comprehensive. Hope to work with him again in the future.”