Certified Building Contractor CBC1265305 · AC & Heating
Why is water leaking from my AC unit into the ceiling?
A straight answer from a Florida state-certified contractor — then what you can check yourself and when to call. Free estimate: (954) 620-7812.
Water coming through the ceiling from an AC is most often a clogged condensate drain line. The air handler pulls moisture out of humid air, and when that water can't drain away, it overflows the pan and soaks the ceiling below.
Less often the cause is a cracked or rusted drain pan, a disconnected drain line, a frozen evaporator coil that thaws, or sweating ducts in a hot attic. Each one has a different fix, so it helps to find which it is before anyone repairs the drywall.
Why it happens
In Florida's heat and near-constant humidity, a cooling system can remove a lot of water from the air every day. That water drips off the evaporator coil into a pan and flows out through a drain line. Algae, slime and debris build up inside that line over time and can block it. The pan then fills and spills, and if the air handler is in an attic or closet above a ceiling, the water goes into the drywall.
The pan itself can also fail. Older metal pans may rust through, and plastic pans can crack. A drain line can sag, come loose at a joint or lose its slope. A safety float switch is meant to shut the system off when the pan fills, but if it is missing or has failed, the unit keeps running and the leak keeps growing.
A frozen coil is another source. Restricted airflow from a dirty filter, a weak blower or low refrigerant can ice up the coil. When the ice melts it can produce more water than the pan can handle. Separately, uninsulated or damaged duct insulation in a humid attic can sweat and drip onto the ceiling, even when the drain is working.
What you can check yourself
Turn the system off
Switch the AC off at the thermostat, and at the breaker if water is near light fixtures or electrical equipment. This stops more water from being produced while you sort out the cause.
Look at the air filter
A clogged filter restricts airflow and can freeze the coil. Replace it if it is dirty.
Check the pan and drain
If you can reach the air handler safely, look for standing water in the pan or a visible drain-line disconnect. Don't climb into a hot attic or work around wiring if you aren't comfortable doing so.
Look for ice
Ice on the coil or refrigerant lines means the leak may come from a frozen coil. Leave the system off and let it thaw, then have the cause diagnosed.
Protect the ceiling
Place a bucket under any drip. If the drywall bulges or sags, a small hole can sometimes let trapped water drain safely, but the damaged section will need professional attention.
When to call a pro
Call a professional if the drain keeps clogging, the pan looks cracked or rusted, ice returns after a new filter, or the ceiling is stained, soft or sagging. Wet insulation and drywall can lead to mold in Florida's humid climate, so it is worth having the ceiling checked after the AC is fixed. Replacing a failed air handler or system usually requires a mechanical permit with inspection and close-out, while clearing a drain or routine maintenance usually does not. Rules vary, so confirm with your local building department.
In Miami-Dade, Broward and Palm Beach counties, we manage the project under our Florida Certified Building Contractor license, CBC1265305. The AC work itself is done by our Florida-licensed air-conditioning subcontractors, who pull the mechanical permit when one is needed (s. 489.113(3), Florida Statutes). Call (954) 620-7812 or use the quote form for a free estimate. We can also coordinate the ceiling repair, which keeps the leak fix and the drywall work under one contractor.
What a pro will do
- Find the actual sourceThe technician checks the drain line, pan, float switch, coil and ductwork to find where the water comes from, rather than just wiping up the symptom.
- Clear and test the condensate drainA blocked line is cleared and flow is tested. A float switch can be added or replaced so the system shuts off before the pan overflows.
- Repair or replace failed partsA cracked pan, loose drain joint or poorly sloped line is corrected. If the coil froze, the technician looks at airflow and refrigerant for the root cause.
- Recommend repair or replacementIf the air handler is badly corroded or the system is aging, we explain the options in a written scope before work starts. A replacement would be done to current SEER2 standards.
- Handle permit and close-out when requiredFor a change-out or new install, our licensed subcontractors pull the mechanical permit, inspections are scheduled and passed, and the permit is closed out.
Related questions
- Is it safe to keep running the AC if it is dripping?
- It is better to turn it off until the cause is found. Running it can add water to the ceiling and may damage the unit if the coil is frozen. If water is near lights or outlets, turn off the breaker as well.
- Can a clogged drain be prevented?
- Regular maintenance helps, including clearing the drain line, checking the pan and changing filters on schedule. A float switch on the drain pan adds a safeguard if the line does block.
- Will the ceiling need to be replaced?
- That depends on how long the water was there and how much it soaked in. A small stain that dried quickly may only need sealing and paint, while wet or sagging drywall and insulation are usually cut out and replaced.
- Does fixing an AC leak need a permit?
- Clearing a condensate drain or routine maintenance usually doesn't. Replacing an air handler or system typically does. Confirm with your city or county building department.
Keep reading
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