DIY AC Maintenance Tip #2: Preventing your drain line from becoming clogged with dirt, dust, and algae is simple, easy, and quick. In the attic you will find your evaporator coil and out of the evaporator coil you will see a PVC pipe. This PVC pipe will usually have an opening somewhere close by. If it does not have an opening, contact your local air conditioning repair company, hopefully us, to install an opening in your drain. On a monthly basis slowly pour one to two cups of bleach mixed with some water into this opening. This will help destroy the algae and build-up of other things that can clog your drain line. Learn more about air conditioner drain lines here!