How to Clean an Air Conditioner Drain

Cleaning the air conditioner drain line prevents water backing up in the drain pan.

Your air conditioner cools your home by removing the moisture from the air inside. When the unit is working properly, the moisture runs through the air conditioner drain line and out of the house. Unfortunately, moisture also breeds mold and mildew. Over time, mold and mildew build up in the drain line and clog the line, preventing water from draining. Cleaning an air conditioner drain line is a two-fold process. Once you clean the line, it is necessary to prevent the line from clogging again.

Things You'll Need

• Wet/dry shop vacuum
• 1 cup bleach

Instructions

1. Turn off the circuit breaker for the air conditioner unit. Go outside and find the end of the drain line. Typically the drain line is coming out of the foundation of your home in the vicinity of the outside unit.

2. Take the filter out of your wet/dry shop vacuum. Place the end of the vacuum hose over the end of the drain line. Hold the hose tight over the line with your hand. Turn on the shop vacuum and allow it to run for one minute.

3. Lift the hose away from the drain line and check for water. The drain line should flow freely. Place the end of the hose over the drain line again and lift it away after another minute. Repeat this process until water drains through the line.

4. Find the end of the drain where it meets the drain pan on the inside unit. Some units have an access point on top of the line while others simply have the access where the line meets the drain pan.

5. Pour 1 cup of bleach into the drain line. Bleach kills mold and mildew and helps prevent them from forming in the first place.

Tips & Warnings

• Pour 1 cup of bleach down the drain line every spring as preventative maintenance.

References

• Danny Lipford: AC Drain Clean Out; Joe Truini
• Web HVAC: Clean Your Air Conditioner Drain Before It Leaks