How do I unclog my air conditioner's drain?

To clear a clogged air conditioner drain line, you can use a few effective methods depending on the severity of the blockage. First, turn off the power to your HVAC system at the thermostat and breaker for safety. Locate the T-shaped PVC vent or access opening near your indoor air handler and pour a mixture of warm water and distilled white vinegar or three percent hydrogen peroxide down the pipe to break down organic slime. If the line remains completely blocked, go outside to the end of the drain pipe and use a wet-dry vacuum to suck out the stubborn clog, debris, and standing water. You can also use a specialized pressurized CO2 cartridge tool designed for HVAC lines to blow the obstruction outward. Once cleared, pour water down the indoor access point to verify that it flows freely out of the outdoor exit.