If you stepped outside today, you already know: Denton County is under a heat advisory, and that 106° heat index isn’t just miserable, it’s dangerous for your home too. Your AC unit has been running nonstop since sunrise, and somewhere in your attic or a closet, a small plastic pipe is working overtime to keep up. When that pipe backs up, it doesn’t leak a little. It floods.
I want to walk you through exactly why this happens on days like today, and what you can check right now, before you come home to a soggy ceiling or a puddle spreading across the closet floor.
Why Extreme Heat Causes AC Condensation Leaks
Your air conditioner doesn’t just cool air, it pulls moisture out of it. That moisture drips off the evaporator coil and runs out through a small condensate drain line, usually PVC pipe, into a drain or outside your home.
On a normal summer day, that system handles the job fine. But on a day like today, with a heat index over 100°, your AC is running longer and harder than usual, which means it’s pulling more moisture out of the air, more often. More condensation means more water trying to move through that same narrow drain line.
If there’s already a partial clog in there, algae, dust, a little sludge buildup, and there almost always is some, a normal day might never push enough water through to cause a problem. A day like today can be the tipping point.
The Overflow Pan Is Your Last Line of Defense
Most systems have a secondary drain pan under the unit specifically to catch overflow if the primary line clogs. It’s a good safety net. But it’s not designed to hold water indefinitely, and if it has its own crack, rust spot, or a clogged secondary drain, that water goes straight onto your ceiling drywall, your attic insulation, or your closet flooring.
This is exactly the kind of water damage Denton homeowners see spike during heat advisories like this one. It’s quiet, it’s usually hidden above a ceiling or behind a wall, and by the time you notice a stain or a drip, there’s often already more moisture back there than you’d think.
What to Check Right Now
- The drain line termination point — usually a PVC pipe near your outdoor unit or exterior wall. Is it actively dripping? A slow, steady drip is normal on a hot day. No drip at all could mean a clog upstream.
- Any ceiling near an attic-mounted air handler — look for new discoloration, soft spots, or a musty smell.
- Closets or utility rooms with an indoor unit — check the floor and the base of the unit for standing water or dampness.
- The condensate pan itself, if you can safely access it — is it full or overflowing?
If you find water where it shouldn’t be, turn off the AC system at the thermostat (not just lower the temperature) until it can be inspected. That stops new water from being added while you sort out next steps.
Why a Small Leak Turns Into a Big Problem, Fast
Here’s the honest truth: it’s not the water itself that’s most expensive. It’s what happens in the days after, when moisture sits inside drywall, insulation, or subfloor without anyone catching it. That’s when you start looking at mold growth and structural damage instead of a simple repair.
This is why, on a day like today, I’d rather you catch it early than “wait and see.” A stain the size of a dinner plate today can mean a whole section of ceiling tomorrow.
If You Find Standing Water
Get the AC off, and get the water addressed quickly. Structural drying isn’t about a shop vac and a box fan overnight, it’s about getting the moisture out of the materials themselves before it turns into something worse. Every hour matters more on a 106° day than it would on a mild one, simply because the AC will keep working just as hard tomorrow.
Not every leak is an emergency, and I’d never tell you otherwise just to get a phone call. But if you’re seeing active water, a sagging ceiling, or a smell that wasn’t there yesterday, that’s worth a same-day look.
If you’re in Pilot Point or anywhere around the North Texas area and you’re dealing with a leak today, give Merlene Mitigation a call. It’s just Josh, no call center, no subcontractor roulette, one person who’ll come look at it, tell you honestly what you’re dealing with, and walk you through what happens next.
And if today isn’t your emergency but you want to be ready before the next heat wave hits, grab our free guide, The First 24 Hours After Water Damage. It’s the same advice I’d give a neighbor, free, no strings.
-Ally
