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AC Leaking Water Inside
in Allen, TX
Allen's humidity, especially in May and June, means your AC pulls a significant amount of water out of the air every day. That water drains out through a condensate line, and when that line gets clogged with algae or debris, water backs up and overflows the drip pan. Water damage to drywall, insulation, or a wood subfloor can happen within 24 to 48 hours if the overflow is bad enough.
Quick Answer
Water leaking from an indoor AC unit in Allen almost always comes from a clogged condensate drain line. The unit pulls humidity out of the air and that water needs somewhere to go. When the drain clogs, the pan overflows and water ends up on your floor or ceiling. Call (361) 320-8102 before the water damages drywall or the subfloor below the unit.
Telltale Signs
Warning Signs to Watch For
- Water stain or wet spot on the ceiling below a second-floor air handler
- Standing water on the floor around the indoor unit
- A musty smell coming from the indoor unit or nearby vents
- The AC shuts itself off and won't restart — a float switch tripped
- Visible algae or slime buildup around the condensate drain outlet outside
Root Causes
What Causes AC Leaking Water Inside?
Clogged Condensate Drain Line
Algae grows inside the condensate drain line year-round in Allen because the line stays damp and warm. Over a few months, the algae builds up enough to block the line completely. Water backs up into the drip pan and overflows onto whatever is below — ceiling drywall, insulation, or the floor.
The Fix
Condensate Drain Flush and Cleaning
A technician flushes the line with a wet-vac or pressurized nitrogen, clears the blockage, and treats the line with an algaecide tablet to slow future growth. This should be done every year at the spring tune-up.
Cracked or Rusted Drip Pan
The drip pan sits under the evaporator coil and catches condensation. In older Allen homes with air handlers that are 15 or more years old, the secondary drip pan can rust through or crack, and water bypasses it entirely. This is more common in attic-mounted units where the pan is rarely inspected.
The Fix
Drip Pan Replacement
A technician replaces the cracked or rusted pan with a new one and checks the float switch to make sure it will shut the system down if the pan fills again. An emergency shutoff float switch is required by current Texas code in attic installations.
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 | Clogged Condensate Drain Line | Cracked or Rusted Drip Pan |
|---|---|---|
| Water overflows the drip pan but the pan itself looks intact | ||
| Water leaks even when the drain line appears clear outside | ||
| AC shuts off on its own and float switch is wet | ||
| Visible rust staining or crack on the bottom of the air handler cabinet | ||
| Algae visible at the drain line outlet on the exterior of the house |
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