How often should I pour vinegar in an AC drain line?

You should pour a cleaning solution of equal parts warm water and distilled white vinegar down your air conditioner condensate drain line once every month during the peak cooling season to keep it running smoothly. Monthly preventative maintenance helps neutralize and dissolve the accumulation of algae, mold, mildew, and bacterial slime before it can bond together and form a solid plug that blocks the pipe. If you live in an exceptionally humid climate where organic growth multiplies rapidly, you might even consider performing this quick flush every three to four weeks. Sticking to a consistent monthly schedule is a cheap, easy, and highly effective way to prevent messy indoor water leaks, avoid emergency plumbing or HVAC service bills, and ensure your system drains properly all summer long.