If your AC’s performance isn’t where you need it to be, the problem may be a clogged AC drain line. The essential component is easy to overlook, but cleaning it can be the difference between AC system issues and a fully functional air conditioner that blows refreshing air.

Cleaning an air conditioner drain line is relatively straightforward. Use the guide below to learn more about AC drain lines, their purpose, and what you should do if your drain line is clogged.

The Purpose of Your AC Condensate Drain Line

Every air conditioner produces condensation. The evaporator coil in the air conditioning unit catches the humidity when air passes over it.

The humidity produces moisture that drips from evaporator coils into the indoor air handler. From the air handler, the excess condensation drips down the AC drain line.

Most drain lines consist of a PVC pipe, but some units have metal lines. The AC drain line connects to the air conditioning and leads outdoors through an exterior wall. The purpose of the air conditioner drain line is to funnel condensation away from the AC unit.

Without the condensate drain line, the system’s humidity will bring extra moisture into the system and your home. The result of elevated humidity indoors includes air conditioner component corrosion, reduced performance, and mold and mildew growth throughout the property.

Many air conditioners have a condensate pan beneath them to catch drips from the water it produces. However, many modern AC models don’t include a drain pan because the drain line transports excess water outside.

Reasons for a Clogged Condensate Drain Line in an Air Conditioner

An AC drain line is a vital cooling system component, but it’s not without its issues. For instance, if the AC unit’s drain line is clogged, water will accumulate in the air conditioning system instead of outdoors. Dirt, dust, algae, and other debris can collect in the AC condensate drain line unless you flush the line regularly.

Symptoms of a Clogged AC Drain Line

There are several ways to check if the drain line is clogged:

  • The drain pan for your air handler is full of water, meaning the condensation is backing up into the HVAC system.
  • The air conditioner won’t turn on or malfunctions often.
  • You have water damage to your property around the indoor unit, specifically around the floor or under the AC fan in the utility closet.
  • Your house has a moldy smell from mold spores blowing through the AC vents.
  • The air blowing from the air conditioner smells foul.

The list isn’t definitive for a clogged condensate line. Though these symptoms may indicate an AC drain clog, the problems could stem from other issues.

However, a quick look at the exit point of the AC drain line may give you more details about the condition of your AC system. When the unit works correctly, you’ll see a small trickle of water coming out of the plastic or metal pipe. A lack of water exiting the line usually indicates a clog.

6 Steps on How to Clean AC Drain Line

You can free an air conditioner drain clog using items you likely have around the house, such as:

  • Cleaning cloths
  • Duct tape
  • Wet/dry vacuum or shop vac
  • Funnel
  • Protective gloves
  • Distilled white vinegar or bleach solution
  • Stiff wire brush


You may need assistance to complete the cleaning, depending on the location and condition of your AC unit, but these are the general steps you should follow.

1. Turn Off the Air Conditioning System

Before flushing the AC drain, turn off the cooling system from the thermostat. You should also shut the system down via the breaker box to ensure that the air conditioner is off.

Most units have a shut-off box near the condenser unit outside. You can also shut the system down using the service disconnect through that box. This way, you know you are working in a safe environment.

2. Locate AC Drain Line

The AC drain line is a rigid plastic pipe with an opening near the outdoor unit, and it connects to one of your house’s walls. There could be a removable access panel you’ll need to take off to locate the drain line. Once you find it, push the wire brush into the end of the pipe to dislodge any clogs that might be present near the exit.

You can also use the wet/dry vac to remove clogs. Attach it to the end of the drain line and seal it with duct tape for an optimal seal. Don’t forget to remove its paper filter to protect it from damage.

3. Disconnect the Hose From the AC Drain

Move indoors and prepare to clean the AC drain line from the opposite end. First, remove the standing water from the drip pan and wipe it clean with the rags.

Next, find the access point by removing the cover from the t-shaped vent tee. Most AC systems have a vent tee. Use the wire brush to dislodge anything from that end of the pipe.

4. Clean Your AC Drain Pipe With Distilled Vinegar or Bleach

Use white vinegar or bleach to clean the AC drain line interior. The cleaning properties of the solutions will further break down buildups within the line. Slowly pour the liquid into the drain using a funnel.

Let the solution sit for a few hours before flushing the pipe with warm water. If the smell of vinegar or bleach is too harsh, flush the drain with soapy water.

5. Check to See if Air Conditioner's Drain Line Is Clear

Ensure that the clogs are gone by having someone pour water into the AC drain while you observe its exit point. The clog is gone if water is flowing freely.

6. Clean AC Drain Line Regularly

Prevent future problems with regular AC maintenance, such as flushing the air conditioner drain line, cleaning the evaporator coil, and changing air filters. Schedule tune-ups with a qualified HVAC company and prevent costly repairs.

Keep Your AC's Drain Line Clean With Professional HVAC System Maintenance

Though cleaning a clogged drain line in your air conditioning is relatively simple, routine maintenance is the best way to prevent AC drain lines from developing clogs. The skilled HVAC technicians from Service Emperor serving Savannah, GA, and the surrounding areas offer world-class HVAC and refrigeration services at competitive prices.

Whether your cooling system issues come from an AC drain line clog or another problem, you can count on our team to identify and repair the problem. Our experienced team also provides the best solutions for preventative maintenance to keep cooling systems running in peak performance. Contact us today at 912-231-5430 to request assistance.