The air conditioning leak nobody looks for
This is the single most common hidden leak we find in Miami-Dade, and it's the one homeowners almost never suspect, because nothing about it looks like plumbing.
Your cooling system pulls gallons of water out of the air every day and sends it away down a small pipe. When that pipe partly blocks, the water backs up and finds a second route out, usually into a ceiling or a wall cavity, where it can run for weeks before anything shows on the surface.
If you have a stain with no plumbing above it, this is the first thing we check. The quickest test you can do yourself is in section three, and it takes about a minute.
Your air conditioning makes gallons of water a day
Cooling works by running air across a coil that's below the dew point, and the moisture in that air condenses on the coil in the same way it does on a cold glass. The water runs off the coil into a pan under the air handler, and out of the building through a small drain line, usually three quarters of an inch of PVC with a trap in it.
In Miami summer conditions, that's roughly one to three gallons per ton per day, so a four-ton system can move well over ten gallons on a hot day. Removing that water is half of what your system is for, but it counts on being able to evacuate that water out of your property. The single thing standing between ten gallons a day and your ceiling, floor, or wall cavity is a narrow pipe that lives in the dark, stays permanently wet, and has nobody looking at it.
It's also why this is a Miami problem in particular. The same system in a dry climate barely produces any, and a partial blockage there may never overflow at all.
The one-minute check, and five other signs
Walk outside while the system is running on a hot day and find the drain stub, a short length of PVC coming through the wall near the condenser. If the system has been cooling for a while and nothing is dripping from it, the condensate is leaving by another route.
A stain with no plumbing above it
A ceiling or upper-wall stain in a hallway, a closet, or a room with no bathroom or kitchen overhead. If there's no supply line up there, condensate and roof are the two candidates, and condensate is by far the more common.
A musty smell that's strongest at a register
If the smell arrives with the airflow and fades when the system cycles off, the source is inside the equipment or the cavity around it. A smell that's strongest in one room and doesn't move is a different problem.
Water in the air handler closet
Standing water, a rusted platform, a damp door frame, or a secondary pan that isn't empty. The secondary pan is a backup that should stay dry. Water in it means the primary route has already failed.
A system that stops and starts on its own
That's usually a float switch cutting the system to stop an overflow, then resetting once the level drops. It's a safety device reporting a blockage, and it's worth treating as information rather than a nuisance.
The house feels humid while it's cooling
Cool and clammy at the same time means the system is dropping temperature without removing much moisture, and standing water in the pan is one of the reasons. That has its own consequences, covered in the mold guide.
A total blockage is often the better outcome. It trips the float switch, the system stops, and you find out immediately. A partial blockage passes just enough water for most of the day and only overflows during the longest cycles, so it announces nothing and runs for weeks.
The stain is where the water stopped
Water leaving a pan doesn't fall straight down. It runs along the top of the drywall, down the outside of a duct, along a hanger strap, or across a truss until it meets a joint, a fixture, or a low point, and that's where it appears. We've traced stains fifteen feet from the air handler, and in one case into a room on the other side of a wall.
So cutting the ceiling under the stain is the wrong first move: it often finds dry framing and tells you nothing, and now there's a hole. The point of finding a leak properly is to open one small hole in the right place instead of three in the wrong ones.
Moisture mapping
Non-invasive meters first, across the whole ceiling and the walls around it, to find the shape of the wet area. The shape is what points back to the source.
Thermal imaging
Wet materials hold temperature differently from dry ones, so a camera shows the path. It doesn't see water, it sees the difference, so it's used alongside meters and never instead of them.
The drain line, end to end
Pan, trap, slope, joints, insulation, and the exterior termination. Most of what we find is in one of five places, and the termination blocked by dirt or a nest is the most common of them. In larger Pinecrest and Kendall houses running two or three systems, we trace every path rather than the one nearest the stain.
A borescope, if needed
A camera through a hole the size of a pencil, so you can see inside the cavity before anyone decides to open it. Full detail on how we run a leak detection.
We're the drying experts
We'll find the water, dry what it reached, document all of it, and tell you plainly what needs to be repaired. We'll hand you a clear description of the fault so your air conditioning contractor can take on the repair, which may include clearing the line, replacing a corroded pan, correcting the slope, or fitting a float switch.
If we find the cause and it isn't ours to fix, we tell you what to ask for. Then, once it's fixed, the drying is verified against readings rather than against a calendar, so nobody has to take anyone's word for it. Same logic as any water damage job, and the same file at the end.
Keeping it from happening again
What people ask us next
How can I tell if my air conditioning is leaking into the ceiling?
Check the exterior drain stub while the system is running on a hot day. If it's been cooling for a while and nothing is coming out, the condensate is leaving by another route. The other signs are a stain with no plumbing above it, a musty smell strongest at a register, standing water in the air handler closet, and a system that shuts itself off and restarts later.
Is an air conditioning condensate leak covered by insurance?
It depends on how the water got out and how long it ran. A component that fails suddenly is often treated as a sudden, accidental discharge. Weeks of seepage through a slowly blocking drain is often treated as deferred maintenance and excluded. The outcome usually turns on evidence, so readings, photographs, and the condition of the line all matter. Ask us before you open the claim: it costs nothing, and the answer sometimes changes what you do next.
How much water does a condensate leak release?
Roughly one to three gallons per ton per day in Miami summer conditions, so a four-ton system can move well over ten gallons on a hot day. Three weeks of that has put more water into a building than a supply line bursting for an hour. A small stain is worth a phone call.
Can I clear the condensate line myself?
Flushing the line and fitting pan tablets is normal maintenance, and your air conditioning contractor will show you how. What we wouldn't do is pour bleach into a line that drains a pan under a coil, or push a blockage further into a section nobody can see. We're not an HVAC company, and when the repair is theirs we say so.