If you can hear your AC running almost nonstop today, you’re not imagining it. With the heat advisory in place and the heat index pushing 105° across Denton County, every air conditioner in North Texas is working harder than it was designed to work for hours at a stretch. And when an AC system runs that hard, that long, something else starts working overtime too: your condensation drain line. Today’s the day it’s most likely to fail — and it can do it quietly, behind a wall, for hours before anyone notices.
Why heat like this causes leaks, not just discomfort
Your AC doesn’t just cool air — it pulls moisture out of it. That moisture collects as condensation and is supposed to drain out through a small line, usually PVC, that runs from the indoor unit to the outside of your house.
On a normal day, that line handles a manageable amount of water. On a 105° heat index day, your system is running longer cycles, pulling more moisture out of the air for more hours in a row, and pushing more water through that same small line. If there’s even a partial clog — algae, dust, a bit of debris — today is the day it backs up and overflows.
That’s the quiet part of an AC overflow. It doesn’t announce itself with a bang. It shows up as a stain on the ceiling below the attic unit, a damp spot near the closet where your indoor unit lives, or water pooling in the drain pan and finding its way past it. By the time you see it, it’s often been dripping for a while.
What to check today, right now
None of this takes special tools — just a few minutes and a flashlight.
- The drain pan under your indoor unit. If your unit is in a closet or attic, look for standing water in the pan or on the floor around it.
- Ceiling below the attic unit. A yellowish stain, a soft or sagging spot, or new discoloration is a sign water has already found its way through.
- The outdoor drain line termination. This is usually a white PVC pipe near your outdoor unit. Water should be dripping from it steadily on a day this hot. If it’s bone dry while your AC is clearly running, that’s a red flag — the water may be backing up somewhere else instead.
- Musty smell near vents or closets. Moisture sitting behind drywall or under flooring often announces itself with smell before it shows visibly.
- Your float switch, if you have one. Some systems have a safety switch that shuts the AC off when the pan overflows. If your AC suddenly stopped cooling on a day this hot, this could be why — and it’s actually doing its job.
If you find water
Don’t panic, but don’t wait, either. A small leak today can mean saturated drywall, insulation, or subfloor by tomorrow — and once that happens, it’s not something a fan and an open window will fix. Moisture trapped inside a wall or under flooring needs real drying equipment to pull it out fully; surface-dry isn’t the same as structure-dry, and that gap is exactly where hidden mold risk lives.
If you catch it early, turn the AC off at the thermostat to stop feeding the leak, mop up what you can see, and get eyes on it — either an HVAC tech for the mechanical side, or a water damage professional if there’s already saturation in drywall, flooring, or insulation.
We’re here if today’s the day
I’m not going to pretend I know whether this is a five-minute clog or something that’s already spread further than it looks — that’s exactly what an inspection is for. Josh has been doing this work for over 12 years, and he’ll tell you straight what he’s seeing and what it actually needs, not what’s easiest to sell.
Merlene Mitigation is based right here in Pilot Point, and Josh personally handles every water damage inspection — no call center, no subcontractor you’ve never met. That keeps things honest, and it keeps the price fair.
If you’re in Denton or anywhere in North Texas and you’re looking at a wet drain pan or a stained ceiling right now, call or text Josh. He’s typically on-site within the hour for situations like this.
And if today isn’t your emergency but you want to know exactly what to do the moment it is, grab our free guide, The First 24 Hours After Water Damage. It’s the same plan we’d walk you through on the phone — just ready before you need it.
-Ally
