Why Is My AC Leaking Water Inside the House?

A brown ring appears on the ceiling, or you find a puddle beside the indoor unit. Nothing else seems wrong. The house is cool, the system sounds normal, and yet there's water somewhere water shouldn't be.

Why is my AC leaking water inside the house? Your system produces water on purpose, as part of cooling. A leak means that water isn't draining where it should. The most common reason is a clogged condensate drain line.

Below, we'll start with what the location of the water tells you, because that narrows things fast. Then we'll cover the five causes and what to do in the next few minutes. Last, we'll explain two devices that may have already saved your ceiling.

Your AC pulls moisture out of the air by design. A leak means that water isn't draining where it should.

Where you see it tells you a lot:

• A ceiling stain points to the attic unit, and it's been going a while
• Water at the indoor unit points to the drain pan or primary drain line
• Dripping outside from an eave is the secondary drain line warning you
• System shut off with water present means a float switch did its job

The most common cause is a clogged condensate drain line. Algae and debris block it, water backs up, and the pan overflows.

Right now: turn the system off at the thermostat and dry what you can reach.

Water where it shouldn't be? See AC leak repair in Southlake.

Before anything else, it helps to know that the water isn't a malfunction. Your air conditioner makes it every time it runs.

Cooling does two jobs at once. It lowers the air temperature and it pulls humidity out of that air. The moisture condenses on the cold evaporator coil, the same way a glass of ice water sweats on a hot afternoon.

On a humid Texas day, a running system produces a genuinely surprising amount of water. Gallons, not drops.

All of it collects in a drain pan beneath the coil. From there it leaves the house through a condensate drain line, and when that path works you never think about it.

So a leak isn't water arriving from somewhere unexpected. It's water that was always being made, failing to leave.

That changes the question you're asking. Not where did this come from, but why did it stop draining.

You already know where you're seeing water. That's the fastest way to narrow this down.

A stain on the ceiling. Your air handler is in the attic, and water has been escaping long enough to soak through drywall. This is the most damaging version, because it had a head start measured in days rather than hours.

Water pooling around the indoor unit. The drain pan is overflowing, has rusted through, or the drain line connection has come loose. Easier to spot and usually caught sooner.

Dripping from a vent or register. Often condensation forming in ductwork, or water traveling along a duct from somewhere else and finding an exit.

Dripping outside from an eave or soffit. That's the secondary drain line, and it's the one people misread most. More on it below.

No water anywhere, but the system shut off. A float switch may have cut power before anything overflowed at all.

Start with where. The list of possible causes gets much shorter once you do.

Five problems account for nearly every indoor AC leak.

1. A clogged condensate drain line. The most common by a wide margin. The line stays warm and damp all summer, which lets algae and biological growth build up inside it. Dust and debris add to that. Water backs up behind the clog and the pan overflows.
2. A dirty filter and a frozen coil. A clogged filter restricts airflow across the coil, and the coil freezes. When it thaws, it releases more water at once than the pan can handle.
3. A rusted or cracked drain pan. Older systems develop this. The line can be perfectly clear and the pan still leaks, since the water escapes before it reaches the drain.
4. A disconnected or poorly sloped drain line. Drain lines work by gravity. A line that was never sloped correctly, or one that has shifted, won't carry water away.
5. A failed condensate pump. Where gravity drainage isn't possible, a pump moves the water instead. When the pump quits, the water has nowhere to go.

Two safety features exist specifically to stop this before it reaches your ceiling. If you've run into either one, you got a warning instead of a damaged ceiling.

The secondary drain line. An attic air handler sits in a secondary pan. That pan has its own drain line, running out through an eave or soffit, and it only carries water when the primary drain has failed.

So water dripping outside above a window usually isn't a roof leak. It's your backup system telling you the primary line is blocked, while the ceiling underneath stays dry.

The float switch. A small device that senses rising water in the pan and cuts power to the system. If your AC shut itself off during hot weather and you later found water, it may have been stopped on purpose.

Neither of these is a failure. Both are the system catching a problem early, which is exactly what they were installed to do.

Both also mean the same thing. The primary drain needs attention now, while the backup is still holding.

Five minutes of the right actions makes a real difference here.

Turn the system off at the thermostat. That stops it producing more water, which stops the leak getting worse while you figure out the rest.

Dry what you can reach. The EPA advises drying water-damaged areas within 24 to 48 hours to prevent mold growth. That window is the reason this matters today rather than next week.

Don't ignore a ceiling stain because the dripping stopped. The material above it is still wet, and drywall holds water long after the visible drip ends.

Don't keep resetting a float switch to get the system running again. It's cutting power because water is rising, and overriding it removes the only thing standing between the pan and your ceiling.

Leave the breaker alone unless you see a visible electrical hazard. The thermostat is the right place to stop the system.

Condensate has a path out of your house. When it ends up on a ceiling instead, something in that path stopped working. We clear the line, check the pan and the float switch, and find out why it clogged. That last part is what keeps you from reading this page again next summer.

Berkeys started in Southlake in 1975. Our licensed technicians also work in Trophy Club, Grapevine, Colleyville, Keller, Westlake, and Roanoke.

We answer calls 24/7. Emergency service requests are prioritized based on technician availability. Southlake homeowners rate us 4.9 stars on Google across more than 1,300 reviews. See what they say about Berkeys in Southlake.

Business Address: 1070 S Kimball Ave Suite 131, Southlake, TX 76092

Call (817) 481-5869 for AC leak repair in Southlake.