Main House Drain advice needed..

Factual Questions
1

We have a ranch style house built in the 1950’s, the main street swer line is probably 60 feet from our house. We’ve had some weird floor drain back ups in our basement. We had the first backup Columbus Day weekend after running the clothes washer in the basement…the washer empties water directly into the main outlet, right by the fron of the house in our basement. We had a local roto-rooter type guy come out and run the power auger through…came back with some tree roots…seemed OK right afterward…

Then a week or so later…same problem, same guy comes out…runs the auger, and pulls out more roots (no charge) …this time runs the auger again all the way out to street…comes back clean…

A week later, again when doing wash…backup. Same guy comes back out (again no charge) …runs auger out to street a couple times…comes back with nothing, but we could hear the water suddenly “woosh” down the main drain again…again tested it by running washer and spinning water out…no problems…nobody could figure out what the problem was…but things seemed to be working again

Today, ran wash again…this time water comes up again through floor drain, not as much as before, but still comes up…the guy said to call again, but what other options should we be exploring?

When he runs his auger down, he says it runs clean out to the street…no hang ups…does not think the line is cracked or damaged…

We’re stumped…any ideas?

2

If you live in a fairly geographically active area, its possible that the line doesn’t have the correct slope anymore(ie the ground raised or lowered, but the chances of that happening without breaking the line are kinda slim.

3

To drain right the drain air vent to the roof has to be clear too. Did you try a half load? maybe less water, less backup?

If it has one that is.

4

Have you recently changed brands of toilet paper ?
Some of them do not break up when wet as easily as others and can build up and clog drains.

5

That washer sounds like it may be the lowest drainage point in the house. I lived in a house that had a toilet in the basement and that used to explode toilet paper at random about once a year. I asked a plumber about that once and he said that it’s the lowest point in the house and of course, about as low as you could get relative to the main line under the street, so any backup in the main street line could wind up affecting that toilet.
Generally speaking, it seems like having plumbing in the basement may be asking for trouble. But that’s only one house worth of experience and one plumber’s advice.