I randomly found this forum and started reading some good information here. I have had the same problem several times for the past 2 yrs now.
Let start with the info. 2 story house built in late 1800's and added onto once.. 1 bath upstairs, 1 down. on crawl space however main line and vent stack runs along outside of house and then into ground. cast iron pipe with some pvc spliced in(not by me). sewer system.
so 3 times in recent years our plumbing has become awful. our plumbing will just cease to work. toilet downstairs will not flush down....will sometimes back up into tub downstairs. tub down will go down slowly or not at all and will make toilet down gurgle along with toilet up gurgle and kitchen sink down gurgle. wash machine when draining will back up into down bathtub. on this recent bout of trouble the kitchen sink will not go down either.
Each time i have rented an auger to run through main line to sewer connection. each time it has made the plumbing work. this last time though it only worked for several weeks before doing the same thing. I have gotten some small roots out but nothing big and there are not trees running along where line is. there are stumps however.
I really believe the vent stack is clogged or the pitch to city connection is not enough or have some failing spots in the old cast iron pipe.
got a quote of $400 to just run a camera through the pipe but would rather just spend the money and replace all the cast iron with pvc and achieve better pitch in process.
questions are about my theories and another is to whether I can connect main line to city sewer? If it is connected at curb I know I can do it. and i know i can dig the trench and run the pipe myself as I have been in the landscaping industry for a long time.
sorry for long post. wanted to be as specific as possible.
thanks for any help or recommendations.