If the drain line from your air conditioner becomes clogged it can cause a bad odor and water to back up into your home and cause damage. The line is easy to unclog with a few simple tools you most likely already have.
Step 1 - Prevent a Clog
Prevention is the best step to keep your condensate drain line from clogging. Routinely remove the drain line from the air conditioner unit and pour about 1 cup of pure bleach through the pipe. If you collect it at the end you can pour it through a couple more times to make sure you cleaned away sludge and possible algae growth. Then rinse with cold, clean water. This will also work on small clogs.
Step 2 - Remove a Clog
Remove the condensate line from the unit and try blowing it out with the compressed air, or an air compressor if you happen to have one. This works well on shorter lines. Flush with bleach and then water as instructed above to clean.
You can do the same procedure but instead use a shop vac to suck the debris that is clogging the drain line out of the pipe. You may get rusty water and some rather smelly gunk. This is normal and is why washing it out with bleach and water is recommended.