Back to blog
A ceiling leaking water due to a clogged AC drain line - Houston AC drain maintenance
Emergency Prevention

Clogged AC drains can spell disaster for your home!

HVAC Maintenance
25 Min Read
Updated: January 15, 2024

AC Drain Line Maintenance Tips Every Houston Homeowner Should Know

Learn how to prevent clogged AC drain lines that cause water damage, flooding, and expensive repairs in Houston's humid climate.

Adams Air

Licensed HVAC Experts - TACLB9265E

1,240+ views

Critical Houston AC Maintenance Alert

Did you know your air conditioner makes about 30 gallons of water each day? In Houston's humid climate, a clogged AC drain can cause catastrophic water damage to your home's interior.

AC drain lines can often clog, and if your indoor AC unit is located in your attic, the water created by the AC system begins to overflow out of the system and naturally drips onto the ceiling below it. This water soaks into the sheetrock, staining and ruining your home's interior.

If the issue isn't resolved quickly, the water will easily soak into the sheetrock to the point where it becomes so saturated that the sheetrock ceiling falls apart, collapses, and leaks massive amounts of water into your home, damaging all of your valuables.

This is why drain line maintenance is so important for every Houston home and should be something every homeowner takes very seriously. Let's explore why air conditioners make so much water, where the water is supposed to drain, how AC drain lines actually clog, and what we can do to protect our homes and prevent clogs from ever happening.

Why Do Air Conditioners Make So Much Water?

Air conditioners make a lot of water. Well, they don't actually 'make' water - they extract and 'squeeze' water out of the air. Since Houston's air is generally very humid, this means our air contains a lot of moisture, which then gets extracted by our air conditioning systems as they operate and cool our homes.

The reason air conditioners 'make' or extract so much water is because air conditioners not only cool down the air in our homes, but they also dehumidify the air by removing moisture from the air, thus lowering both the temperature and the humidity within our homes.

All of this water the AC system pulls out of the air is then collected in a small drain pan located inside of the air conditioner's indoor evaporator coil section. If the system's drain line isn't clogged, the AC system then dumps all of this water from the drain pan into the drain line and (hopefully) drains the water away into your home's plumbing.

Common Drain Connections

Sink Connection

AC drain lines typically tie into kitchen or bathroom sink plumbing, which can clog frequently.

Plumbing Stack

Better builders drain AC systems directly into the 3-inch plumbing stack, which is harder to clog.

Plumbing Vent

The best setup ties into the plumbing vent, which rarely clogs and requires shorter drain lines.

AC drain line connecting to sink plumbing - Houston AC drain maintenance
AC drain lines often tie into sink plumbing

Why Do AC Drain Lines Clog?

AC drain lines generally clog due to the growth and formation of bacteria within the drain line. Very rarely can outside objects get into the closed drain system.

The cold, damp, and dark environment inside a plastic AC drain line happens to be the perfect breeding ground for bacteria, slime, and sludge. Over time, this gunk forms and, without proper care and treatment, the AC drain lines soon clog because of the buildup.

Murphy's Law Alert: AC drain lines tend to clog at the worst possible times.. like, when you're not home or returning from vacation!
Sludge buildup in AC drain line - Houston AC drain cleaning
Sludge buildup in untreated AC drain lines
Collapsed ceiling from AC drain leak - Houston water damage prevention
Disaster Example

Clogged AC drains are no fun at all!

What Can I Do to Prevent My AC Drains from Clogging?

In order to keep the slime and sludge from forming in your AC drain lines, you have to keep your drain lines treated with bleach or chlorine tablets just like a pool.

Treatment Options

Condensate Pan Tablets (Recommended)

Dissolve over time, coating the drain line and treating it longer than liquid bleach. Available on Amazon or Home Depot.

Liquid Bleach (Alternative)

Works but flows through quickly. Use if tablets aren't available, but tablets are more effective.

Buy on Amazon

You can search amazon for 'condensate pan tablets' or click here to buy the kind shown in this blog.

AC drain tablets - Houston AC drain maintenance products
Condensate pan tablets prevent slime growth

Important Note

Condensate tabs or bleach won't clear or unclog your drain lines if they are already clogged. They will only prevent future clogs from forming.

How to Add Treatment to Your AC Drain Lines

Locate Indoor Unit
Find Drain Lines
Add Treatment
Monitor System

Easy Access Method

Some HVAC systems have a built-in accessible area where you can drop tablets or pour bleach directly into the drain line. Look for a "T" shaped tee adapter on the drain line.

Pro Tip: If your system has this setup, maintenance is quick and easy!
Pouring bleach into AC drain line - Houston AC maintenance
Easy access drain line treatment

Advanced Method: Accessing the Evaporator Coil

If your system doesn't have easy access, you'll need to open the evaporator coil housing:

  1. Remove tape and screws from the front cover
  2. Locate the internal drain pan under the evaporator coil
  3. Add tablets to the primary pan (not the external emergency pan)
  4. Replace cover with all screws and tape
Safety Warning: The blower motor will blow the cover off if not properly screwed on. This can cause system damage!
Open HVAC evaporator coil showing primary drain pan - Houston AC service
Primary drain pan under evaporator coil

How Often Should I Treat My Drain Lines?

Condensate Pan Tablets
3-6 Months
Follow manufacturer instructions
Liquid Bleach
Monthly
During cooling season

Professional Service

Adams Air clears and treats AC drain lines during our preventative maintenance visits, ensuring your system stays protected year-round.

DIY Schedule

Add bleach monthly when changing air filters during Houston's cooling season for best results.

Additional Protection: Float Switch Installation

If you're still concerned about your AC drain lines, an electronic switch called a float switch can be added to your HVAC system. This sensor detects if water level rises to the point where it's about to overflow.

Automatic Protection

Shuts off AC system when water level gets too high

Early Warning

Alerts you to drainage problems before damage occurs

Property Protection

Prevents water damage even when you're away

AC float switch installation - Houston AC safety device
Float switch prevents AC overflow

Emergency Response: If Your Drain Line Clogs

AC drain lines are a serious topic when it comes to HVAC systems because they can cause extensive and expensive water damage to your home - destroying ceilings, furnishings, floors, walls, electronics, and more.

DIY Clearing Methods

  • Cut open and clear with wet/shop vacuum
  • Blow out with compressed air or nitrogen
  • Use a pump to force blockage clear

Safety Precautions

  • Always test with water before turning system on
  • Keep wet vacuum nearby during work
  • Monitor ceiling for water stains after repair

When to Call Professionals

If you're unable to clear the drains or if water damage has already occurred, contact Adams Air immediately for professional Houston AC drain repair and water damage assessment.

Need Professional AC Drain Line Service in Houston?

Adams Air provides expert AC drain line cleaning, repair, and replacement services throughout Greater Houston. Our licensed technicians ensure your system drains properly and protects your home.


Tags:
AC Drain Maintenance
Houston HVAC
Water Damage Prevention
Clogged Drain Lines
Home Maintenance
Adams Air
logo-light

Adams Air is the No.1 HVAC contractor in Houston.
Why settle for less? Get the best AC service today.

Name

Adams Air Conditioning

Address

38074 Klaus Ln
Pattison, TX 77423, USA

© 2025 Adams Air Conditioning & Heating | LIC: TACLB9265E