Every June, the same question lands in our inbox: “My pool is losing water — do I have a leak, or is this just Vegas?” It’s a fair question. In the hottest stretch of a Las Vegas Valley summer, an uncovered pool can lose around a quarter inch of water a day to evaporation alone, and a windy week can push that higher. That’s real water, and it looks alarming on the tile line. But evaporation and a slow leak behave differently, and you can usually tell them apart from your own deck in about a day. Here’s how we sort it out — and what professional pool leak detection looks like when the simple checks point to a real problem.
First, rule out evaporation
Evaporation in Southern Nevada is not a rounding error. Single-digit humidity, intense sun, and warm night air pull a surprising amount of water out of a pool, which is part of why the Southern Nevada Water Authority pays so much attention to outdoor water use. Wind matters too — moving air strips the humid layer that sits just above the water surface, so a breezy backyard evaporates faster than a sheltered one a few streets over.
The practical point: a dropping water level in July is not, by itself, evidence of a leak. Before you start picturing excavation, measure what’s actually happening. That’s the whole purpose of the bucket test.
The bucket test: twenty minutes of setup, one honest answer
This is the same first step a leak professional would ask you about, and it costs nothing.
- Fill the pool to its normal level and turn off the autofill if you have one.
- Set a bucket on the top step (or a ledge) and weigh it down with a rock or brick so it can’t tip or float.
- Fill the bucket so the water inside matches the pool’s water level outside — same height, same exposure to sun and air.
- Mark both levels: a strip of tape inside the bucket, another on the bucket’s outside or the tile for the pool.
- Run the pool normally for 24 hours, then compare. Evaporation affects both marks equally.
- If the pool dropped noticeably more than the bucket, the pool is losing water somewhere evaporation can’t explain.
One day of patience replaces weeks of guessing. If the two marks fall together, you’re watching the desert do what it does, and a cover or windbreak will save you more water than any repair.
Pump on vs. pump off: the clue most homeowners miss
If the bucket test says leak, run it again — once with the pump running on its normal schedule, once with the system off for 24 hours. The comparison narrows the search considerably. Losing more water with the pump running points at the pressure side of the plumbing, where circulating water is being forced out through a fault. Losing more with the pump off suggests the suction side or something in the shell itself. Losing the same amount either way usually means a structural fault — and if the level eventually stops dropping on its own, the leak likely sits right around the level where it stopped. That single observation can be the difference between a targeted fix and a fishing expedition.
Where slow leaks actually hide
In the pools we service across the Las Vegas Valley, the slow leaks we confirm cluster in a handful of places, and almost none of them are dramatic cracks in open plaster:
- The skimmer throat — the joint where the plastic skimmer body meets the concrete shell is the single most common culprit we see.
- The light niche and its conduit — water follows the wiring conduit out of the niche and away from the pool.
- Return and cleaner fittings — small gaps behind the eyeball fittings or at the wall step.
- Autofill assemblies — the device meant to manage your water level can itself be the thing leaking.
- Underground plumbing — less common than homeowners fear, but real, especially where lines were stressed by settling soil.
A word of caution: if your suspect is the light niche, stop there. Pool lights involve underwater electrical wiring, and the niche, bonding, and conduit are not a place for trial-and-error — water intrusion and electricity in the same fixture is a hazard, not a project. Have a licensed professional open it up.
How professional pool leak detection works
When the bucket test and the pump-on/pump-off comparison say “real leak,” pool leak detection moves from observation to instruments. We pressure-test the plumbing lines one at a time, isolating each run and watching whether it holds — a line that bleeds pressure has a fault somewhere along it. Electronic listening equipment narrows the spot: pressurized air escaping into wet soil makes a sound a hydrophone can locate from the deck, often within a foot or two. Dye testing confirms faults in the shell, skimmer, and fittings once the search area is small. The craft is in the sequence — cheap, broad tests first, precise ones last — so the answer arrives without tearing anything up to find it.
If you’ve already done the bucket test and the pool failed, you’re ahead of the game. Bring those numbers to our repair team and the diagnostic starts from evidence instead of zero. You can schedule a leak check online and mention what the test showed.
Why waiting costs more here than in most places
Two Vegas-specific factors make a slow leak worth chasing promptly. The first is the autofill problem: because so many Valley homes have automatic levelers, leaks routinely run invisible for months — the level never drops, the water bill just climbs. On a recent Henderson stop, the giveaway wasn’t the pool at all; it was the homeowner mentioning their water bill had been creeping up since spring. The autofill had been quietly feeding a skimmer leak the whole time.
The second is our water itself. Lake Mead source water is among the hardest in the country, and every gallon that leaks out gets replaced by a gallon of fresh minerals. A leaking pool concentrates calcium faster, which shows up as scale on tile and inside equipment. The leak costs you water, then costs you again in chemistry. If you’re replacing water anyway, it’s worth doing it efficiently — the EPA’s WaterSense program has useful guidance on outdoor water waste.
There’s also a structural angle. Water escaping through or under the shell doesn’t just disappear — over time it can erode the material supporting your deck and coping. Slow leaks rarely become emergencies overnight, but sudden, rapid loss is a different animal: if you’re losing an inch or more a day, keep the equipment from running dry and call for emergency service rather than waiting on a routine slot.
One more practical note: this is a case where regular eyes on the pool genuinely pay off. Our techs log water level along with chemistry on routine maintenance visits, and several of the leaks we’ve caught early were flagged because the level looked wrong week over week — before the homeowner had noticed anything.
Pool leak questions we hear most
How much water loss is normal for a Las Vegas pool in summer?
In the hottest, driest stretch, an uncovered Valley pool can lose roughly a quarter inch a day to evaporation, more on windy days. If you’re losing noticeably more than that — or the level keeps dropping after a bucket test says it shouldn’t — it’s time to look for a leak.
Does a pool leak always show a wet spot in the yard?
No, and in our desert soil it usually doesn’t. The ground absorbs and wicks away small amounts of water quickly, so a slow plumbing leak can run for months without a visible damp patch. A dry yard is not evidence of a sound pool.
Can I do a dye test myself?
On a reachable suspect spot, yes — pump off, water fully still, a little dark food coloring released near the area. If dye pulls toward a crack or fitting, you’ve found something. In practice the water is rarely still enough, which is why pros pair dye with other methods.
Will an autofill device hide a leak?
Yes. Autofill systems quietly top off whatever the pool loses, so the level never drops and the leak goes unnoticed. The tell is usually the water bill. If yours has crept up without explanation, shut the autofill off for 24 hours and watch the level.
How quickly should I act on a suspected leak?
A slow leak is rarely an overnight emergency, but it doesn’t improve on its own, and escaping water can undermine decking over time. Rapid loss — an inch or more a day — deserves a same-week call, and sudden major loss is emergency territory. Don’t let the pump run dry.
If your pool is failing the bucket test, the next step is professional pool leak detection — not a guess, and not a panic. We’ll confirm what you found, isolate where the water is going, and give you a clear picture of the fix before any work starts.
Schedule Service · Contact Our Team
This article is for general educational purposes. Pool chemistry, equipment, and electrical work involve real safety risk — if anything in your system is unfamiliar, call a licensed pool professional or the relevant utility before making changes. JNJ Pools is licensed in Nevada, Contractor License #0088611.