Clogged AC Drain Line? Here’s How to Fix It Yourself

If your AC stops working, leaks water, or smells funky, the problem might be a clogged AC drain line. It’s a simple issue with a simple fix — no HVAC tech needed. And with prices going up everywhere, DIY fixes like this can seriously cut your home maintenance costs. And in today’s economy, every dollar counts.

Learning how to handle small home fixes like this can save you hundreds in service calls and prevent further issues. That’s why it’s important to have Fix It First DIY’s checklist to stay on top of these tasks.

Here’s how to clear a clogged AC drain line using a few basic tools and a little elbow grease.

What Causes a Clogged AC Drain Line?

Your AC pulls moisture from the air as it cools your home. That water drains outside through a small PVC pipe. Over time, algae, mold, dust, or debris can build up in the pipe and block it. When that happens, the water backs up into the unit or your home. Some units have what is called a condensate safety switch that will cause the

Signs Your AC Drain Line is Clogged:

• AC unit leaking water indoors
• AC stops cooling properly
• Visible water in the drip pan
• Moldy smell or increased humidity

What You’ll Need:

• Shop vac (wet/dry vacuum)
• Vinegar or bleach solution
• Measuring cup or funnel
• Optional: drain snake, pipe brush, or garden hose

Step-by-Step: How to Clear a Clogged AC Drain Line

1. Shut off the power
Flip the breaker and turn off the thermostat.

2. Find the drain line
It’s the white PVC pipe connected to your indoor AC unit (usually near your furnace or in a closet).

3. Open the cleanout cap
This is where you’ll pour in the cleaning solution.

4. Add vinegar or bleach
Use 1 cup of white vinegar (or 1:1 bleach/water). Let it sit 30 minutes to kill mold and loosen buildup.

5. Vacuum the line from outside
Connect your Shop-Vac to the end of the line outside your home. Run it for a few minutes to suck out the clog.

6. Flush with water
Pour clean water into the line to make sure it’s draining freely.

How to Prevent Another Clog:

• Flush monthly with vinegar
• Replace air filters often
• Keep the area around the unit clean
• Consider adding a safety float switch

Why DIY?

Calling a pro to fix a clogged AC line can cost $100 or more. Doing it yourself takes 20–30 minutes and costs next to nothing. With money tight and ACs working overtime, this is one DIY task that really pays off.