Pool leak detection starts with one question: is the water actually leaking, or is it evaporating?
In Colorado, that question is harder than most guides admit, because evaporation at altitude runs higher than the sea-level numbers people find online. In this article, Brad, a service maintenance technician at Colorado Pool + Spa Scapes, explains how to tell the difference, what the bucket test can and cannot prove, why freeze-thaw is behind so many of the leaks we find, and what a professional leak detection visit actually involves from start to finish.
Evaporation or Leak: How to Tell the Difference
The number alone will not tell you. The pattern will.
“Evaporation up here is worse than whatever figure you found online,” Brad says. “Those quarter-inch-a-day numbers are written for sea level. With our dry air, wind, and sun, an open pool can lose more than that, and a hot tub loses even faster because it is warm water sitting in cold, dry air.”
Evaporation responds to conditions. It slows dramatically under a cover and speeds up on windy days. A leak does not care. It loses the same amount covered or uncovered, calm or windy. If you are topping off on a fixed schedule and the weather never changes that schedule, treat it as a leak until proven otherwise. For a full self-check before calling anyone, see our guide on whether your pool is losing water or just evaporating.
What the Bucket Test Proves and What It Misses
The bucket test answers one question: is the pool losing water faster than the air is taking it? Place a bucket on a pool step, fill it to match the pool’s water level, mark both, and compare after 24 hours with the pump running. If the pool dropped more than the bucket, water is going somewhere it should not.
Where it falls short
It cannot tell you where the leak is. It misses leaks that only open under pump pressure. And slow leaks disappear into its margin of error entirely.
“A tenth of an inch a day is invisible in a home bucket test,” Brad points out. “But that same tenth of an inch is still tens of thousands of gallons over a year.”
People also run it wrong constantly: pump off when it should be on, kids splashing during the test window, or wind skewing both marks. A clean bucket test result is useful. A messy one proves nothing either way.
What a Professional Leak Detection Visit Looks Like
The visit starts with questions, not equipment. How fast is the water dropping? Does the loss change with the pump on versus off? When did it start? That conversation alone usually cuts the search area in half. If the loss stops when the pump is off, the problem is in the pressure-side plumbing before anything gets tested.
From there, the process is systematic:
| Step | What it finds |
|---|---|
| Dye testing | Leaks at fittings, light niches, skimmers, and returns, where dye visibly pulls toward the opening |
| Pressure testing | Failed underground plumbing runs, isolated and tested one line at a time |
| Acoustic listening | The location of underground leaks, where pressurized air escaping the pipe can be heard from the surface |
| Shell inspection | Liner punctures on vinyl pools, structural cracks and skimmer-throat failures on gunite |
“The goal is to leave with a mark on the ground, not a theory,” Brad says. “The repair should open up one spot, not dig up your yard.”
Our leak detection crew locates leaks in both the pool or spa shell and the underground plumbing, and the same team is equipped to repair what it finds.
Why Colorado Breaks Plumbing: Freeze-Thaw
Freeze-thaw ground movement is one of the most common root causes behind the leaks we diagnose, and it shows up in predictable places.
The skimmer
The skimmer is the number one failure point. It sits at the surface, full of water, right in the frost zone, and it cracks at the throat where it connects to the pool shell.
Winterization gaps
Second is plumbing that was never blown out completely, or a line with a low spot that held water through the winter. One missed section can fail quietly for years before the loss becomes visible.
Ground movement
Colorado soil moves with the freeze-thaw cycle, and that movement puts stress on rigid pipe and shell penetrations season after season. As Brad puts it: “I have opened up pools that were winterized pretty well for five straight winters, and there is one fitting that has been slowly failing the entire time.” The same shoulder-season cycling that damages equipment, covered in our article on pool and hot tub maintenance in Colorado, is what eventually opens these leaks.
What Waiting Costs
Water goes exactly where you do not want it. Under the pool, a sustained leak washes fine material out of the soil and leaves voids, which leads to settling, cracked deck slabs, or shell movement. Near the house, a migrating leak can end as a foundation problem that costs more than the entire pool repair would have.
Winter compounds it: leaking water saturates the soil, the soil freezes and heaves, and structural damage accelerates. Autofill systems hide all of it. The water level never drops, everything looks normal, and the only symptom is a water bill that has been climbing for a year.
Finding it early is the difference between a repair and a rebuild. If your pool or spa is losing water and the bucket test has not cleared it, call us at 970-945-8775 and our team will schedule a detection visit.
What to Do While You Wait for Your Appointment
A few things help, and a few things make the diagnosis harder:
- Keep the water topped up. The pump should not run dry, and in cold weather, half-empty lines freeze faster than full ones.
- Track the loss. A piece of tape at the waterline and a daily note, including whether the equipment was running, is genuinely useful data for the technician.
- Photograph any wet ground. Soggy spots dry out and disappear before the visit.
- Do not add extra chemicals. You are paying to treat water that is leaving.
- Do not seal fittings with silicone. Improvised sealant covers the exact points dye testing needs to check.
- Do not shut the system down in cold weather unless a technician tells you to. Still water in a Colorado cold snap creates a new problem on top of the leak.
How Colorado Pool + Spa Scapes Handles Leak Detection
Most people who call us are not sure they have a leak at all. That is normal, and it is the right time to call, because the callers who waited a year are the ones whose repair became excavation. Our leak detection team locates leaks in shells, fittings, and underground plumbing using pressure testing, dye testing, and listening equipment, and because the same company handles maintenance and repair across our service range, the visit ends with a plan, not just a diagnosis.
If the loss turns out to be evaporation, you will know that too, and knowing costs a lot less than guessing.
Ask a Technician: Pool and Spa Leaks in Colorado
A homeowner notices the water level keeps dropping. How do they know if it is real?
First, evaporation up here is worse than whatever figure you found online. Those quarter-inch-a-day numbers are written for sea level. Dry air, wind, strong sun, altitude, an open pool here can lose more than that no problem, and hot tubs are worse because you have got warm water sitting in cold dry air. That thing steams away. So the amount alone does not tell you much. What tells you is the pattern. Evaporation changes with conditions, slows way down under a cover, speeds up when it is windy. A leak does not care. Same loss, covered or not, calm or windy. If you are topping off like clockwork and the weather does not change your schedule, I would bet on a leak.
When does the bucket test work, and when does it miss something?
It answers one question okay: am I losing water faster than evaporation. Bucket on the step, fill it to the pool level, mark both, come back in 24 hours. Pool dropped more than the bucket, you have got a loss. That is it though, that is all it tells you. It does not say where. It will not catch a leak that only opens up under pump pressure. And people botch it constantly. Pump off when it should have been on, kids cannonballing during the test, wind messing with both marks. The other thing is slow leaks just disappear into the margin of error. A tenth of an inch a day, you will never see that in a bucket test, and that is still a massive amount of water over a year.
Are there leaks that look minor but point to something bigger?
Oh yeah. A drip at the equipment pad, at a union, that is usually just a gasket, no drama. But slow loss plus damp ground out in the yard, away from anything, that is an underground line, and those do not stay small. A crack that only weeps in spring, that can mean the shell moved over the winter. That is not a patch, that is a structural conversation. Hot tubs have their own version, a leak that only shows up at temperature. Fitting expands when it is hot, opens up, closes when it cools. Those are always buried deeper in the cabinet than the drip makes it look. The size of the drip tells you nothing. I have chased tiny drips into big jobs and big-looking puddles into ten-minute fixes.
What does a detection visit involve, and what happens after your team finds the leak?
It starts with the story: how fast it is losing, whether it changes with equipment on versus off, when it started. That alone usually cuts the search area in half. Then it is systematic: dye testing at suspect points like fittings, lights, skimmers, and returns, pressure testing individual plumbing runs by isolating and capping them, and listening equipment to hear where pressurized air escapes underground. The goal is to leave with a marked location, not a guess, so the repair opens up one spot instead of trenching a yard. Once we find it, the same team that located it handles the repair, so you are not getting handed off to someone else who has to start from scratch.
Frequently Asked Questions
How do professionals detect a pool leak?
Technicians combine dye testing at fittings and skimmers, pressure testing of individual plumbing lines, and acoustic listening equipment that locates underground leaks by sound. The process starts by comparing water loss with equipment on versus off, which narrows the search before any testing begins.
Can a pool leak damage a house foundation?
Yes. A sustained leak saturates the surrounding soil, and water migrating toward the house can compromise foundation waterproofing. In Colorado, saturated soil also freezes and heaves, accelerating structural damage. Leaks near a structure should be located and repaired quickly regardless of how small the loss seems.
Do pool leaks get worse over time?
Almost always. Escaping water erodes the soil around the failure point, freeze-thaw cycles widen cracks, and pressurized leaks enlarge under normal pump operation. A leak that loses a small amount today typically loses more each season, which is why early detection costs far less than delayed repair.
How long does pool leak detection take?
Most residential detection visits take a few hours, depending on pool size and how much plumbing must be isolated and tested. Cases with multiple leaks or extensive underground runs can take longer. Giving the technician your water-loss history speeds the process considerably.
What should you do while waiting for a leak detection appointment?
Keep the pool topped up so the pump never runs dry, track daily loss with tape at the waterline, and photograph wet ground. Do not add extra chemicals or seal fittings with silicone. As Brad notes, improvised sealant covers the exact points dye testing needs to check.