Sewer Hell

This the long sordid drama of the plumbing probs ive been having the past month. First there was sewage in the yard, apparently the previous owners took off the clean off cover the last time it was overflowing. I live in a house made in '56. All the plumbing is in a line on the back side of the house......I have a master bath shower (1) then a washer (2) then a dishwasher/kitchen sink(3) the clean out valve then another bathroom. This cleanout has been cleaned with a flush bag and then augered with an electronic cutting blade type. It got a small amount of tree roots. Copper sulfate was added as bottle instructed. My prob is this.......when ever (1) or (2) or (3) are used, it backs up into the yard.....I have been told that between (1) and (2) is regular pvc that is about 6 yrs old. rest is cement pipe............HELP!!!! The previous owners did relate a story to me about how once the house totally backed up and they took an electric auger up on the roof and cleaned the vent pipe's out and it solved the problem....any truth to this you think?? I reiterate sincerely..........HELP!!!

drain

Going onto the roof is usually only necessary when there is no cleanout. I would seriously doubt that you have cement pipe under the house unless it was built at the turn of the 19th century. I seldom try to second guess another's work, but also never believe what they say until I have checked myself.

I'd suggest you have a licensed plumbing contractor evaluate your sewer. You can't rely on what someone says or thinks, and you can't rely on the accuracy of what the previous owner did or didn't do. You need the straight facts, and those can only be determined by a real professional on site. This could be a very expensive-to-fix problem, so you've got to have expert and reliable information so that when if is finally repaired, it will be done right the first time.