Washer stand pipe overflowing
Please help! We live in a 1950's ranch home with a basement on a septic system. We have had plumbers out at least 5-7 times due to our washer discharge overflowing out of the standpipe. Each time they snaked the drains and were good for a few months. The drain slowly gets worse after its snaked out. It will start with a small amount of water out of the standpipe which flows to the floor drain and progress until, at the worst, having an inch of water backed up in our utility room. (this is also in the basement by the way). I just. Borrowed a friends hand snake and snaked our floor drain trying to save money. I don't know how long the snake is fr sure but I sent the whole thing down the drain. (it has a spade tip). We've had cameras in clean outs in our yard showing that the pipes seem to be flowing fine out there. We also have a toilet and sink in this room that I believe are tied together under the basemen floor. (I've plunged the toilet and the floor drain water goes up and down and the sink gurgles). Our plumber believes that we should jackhammer the floor up and replace all the plumbing with wider PVC. This is going to be fairly expensive and if it's not necessary we would rather not throw the money away.
This has occurred multiple times after it has rained a decent amount but I wouldn't think that rain should affect our drains because they go into a septic system.
The previous owner did mention something about having a sink hole in the backyard because of a collapsed tile but replaced it and we now have a PVC clean out pipe in our yard. (this is where the camera went in and viewed the basement toilet and sink water flowing freely) we also have another clean out just outside our foundation that I can see water flowing through from the master sink and kitchen sink without obstruction)
I also believe our standpipe might be a little small for our washer as we have an HE washer and the standpipe that it drains into is no more than 1 1/2 inches wide. When it overflows the fibers seem to be quite thick and when they harden I can see how it can clog a pipe...
Not sure if this matters or not but we have a fairly large family and are constantly doing laundry. We ha e a dishwasher and a garbage disposal in the upstairs kitchen sink. The previous owners also installed something I the septic tank to help it break up different matter in it which is wired into a separate breaker system in our detached garage.
Any advise or guidance? Sorry this is so long but in trying to et all info out to you in one shot.
Thanks for your time