I came to this site because after living with a drain that constantly got clogged for 15 years, I finally found a quick and cheap way to clear it. The problem was the main drain that leaves the house and goes to the septic tank. No tree roots anywhere near. I gave up using my disposal a long time ago in case that was the culprit. I've tried foaming and non foaming chemicals (septic tank friendly of course), from cheap to ridiculously expensive - all ineffective.
To provide what has always only been temporary relief, I used one of the expanding rubber bulbs that goes on the end of a hosepipe (highly recommended BTW). But this drain would always get stopped up after a few days for no good reason, backing right up into the house.
I have used a product called Awesome for years, it's a degreaser that Dollar General sells and it works wonders for kitchen cleaning. A light bulb went on in my head and I bought the biggest bottle they sell. After clearing what crap I could with the bulb, I lobbed the whole bottle down the drain, let it sit and then dumped a huge pot of boiling water down after that, followed by the water from a hot laundry load. I ran the hosepipe on full for 30 minutes, and not a drop came back to haunt me.
IT WORKED!
