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AC Drain Line Clog
in Plano, TX
Your AC removes moisture from the air inside your home and sends it out through a drain line, usually a PVC pipe that exits through the attic or a wall. Plano's summer humidity is high enough that this drain line handles a lot of water every day, and algae grows fast in the warm, wet conditions inside the pipe. A clogged drain is one of the most common AC service calls in North Texas.
Quick Answer
AC systems pull moisture out of your air and drain it away through a small pipe. In Plano's humid summers, that pipe can clog with algae and debris in as little as one season. When it backs up, water overflows and can damage ceilings, walls, and floors. Call (469) 960-3779 if you see water near your indoor unit or notice a musty smell.
Telltale Signs
Warning Signs to Watch For
- Water pooling on the floor or ceiling below the indoor air handler
- A musty or moldy smell coming from the vents
- The AC shuts off on its own and won't restart right away
- A drip pan under the air handler is full of water
- Water stains on the ceiling near the attic unit
- High humidity indoors despite the AC running normally
Root Causes
What Causes AC Drain Line Clog?
Algae Buildup in the Drain Line
Warm, moist air sits inside the drain line whenever the AC runs, and algae grows quickly in those conditions. Plano's summer heat keeps attic temperatures above 130 degrees, which makes algae growth in attic-mounted drain lines even faster. Once the blockage forms, the drain pan fills and water finds the next place to go, which is usually your ceiling or floor.
The Fix
Drain Line Flush and Algae Treatment
A technician flushes the line with a vacuum or pressurized air, clears the blockage, and applies a diluted treatment to slow algae regrowth. Pouring a small amount of diluted bleach into the access port a few times a year is a simple step homeowners can do themselves.
Debris or Sediment Blocking the Line
Dust, insulation particles, and other debris from the air handler can wash into the drain line over time and build up into a physical plug. Homes in the older parts of Plano near the historic downtown area that still have original fiberglass duct liner are more likely to shed material into the drain system.
The Fix
Drain Line Clearing and System Cleaning
A technician clears the blockage and inspects the drain pan and coil for related debris. If the air handler's interior is pulling in dust and shedding material, cleaning the coil and drain pan together prevents the problem from coming back quickly.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Algae Buildup in the Drain Line | Debris or Sediment Blocking the Line |
|---|---|---|
| Drain line exit outside the house has no drip even during a hot day of AC use | ||
| Visible green or black growth inside the drain access port | ||
| AC trips the float safety switch and shuts off repeatedly | ||
| Water in the drain pan is cloudy or discolored | ||
| Debris visible in the drain pan along with standing water |
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