Answer: -Is it possible you have roots growing in the sewer drain pipes? We have that problem, and once a year or so we hire a plumber to come over with a "power snake" that cuts the roots and removes them. There is a large company called "Roto-Rooter" that provides this service as well. -We have our main drain power snaked about every 18 - 24 months. We have a ugly "weed maple" tree in the front yard that likes to grow it's roots in the drain. After two backups, we now just have this done as a preventative measure. The company we use gives a 12 month guarantee, which is void if you flush feminine products. We pay $75-$80 for this service, and let me tell you, it is money well spent. I don't know what the machine would cost to rent, but I do know hubby would rather pay someone to do the job. It's a dirty dirty job.