My entire outside sewer pipe system was replaced from the house to the sanitary sewer main.
I have a slab house and my laundry room is ~ 20 feet in from that outside wall.
Several times sewage has backed up and out of my floor drain in the middle of the laundry room.
The same plumber who replaced the outside line rodded the inside line; he encountered very slight resistance.
He didn’t use too large a diameter auger head as the inside pipe is over 40 years old.
Rusty, corroded pieces could break off and cause or exacerbate such blockage.
I’m not sure, but these backups seemed to coincide with very cold outside temperatures.
For sure that was true the only two times it occurred after the outside line was replaced.
Perhaps the inside line was frozen and blocked with ice; no further backups since weather warmed.
Plumber mentioned may be issues with 40 years of grease, soap, and lint building up in the line.
But then why would the problem go away?
What do you think?
Thank You!

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Thanks everyone for taking time to reply. I know the line has to be scoped out with a camera before making repairs. In the meantime, I was just curious what others thought about my freezing/ice blockage theory.



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I think he should use the proper sized head to clear the whole line, not just make a tiny hole through whatever is stopping it up.

A well placed sewer camera, in the hands of an expert, will produce the best results and determine where the restriction of blockage may be. Question is.... do you really want to know?

Best Wishes

In my book....Forty years is new construction.Sheetrock and milled lumber defines the difference for me. Maybe I'm just getting old, but if I could have built the house,it's hard to wrap my head around it.

I kinda figure anything with lead involved is old, anything with plastic in the ground is new, and the rest is average age.