This past Friday we discovered that our septic tank had a drainage problem and had reached it's limits, backing up into the washing machine drain in the basement. That drain is the only drain in the basement, the lowest in the house. Unfortunately, I had just
remodeling that side of the basement, new walls, new floors, the works. The flooring is shot, walls are still good though (according to the pros at ServPro). We got the septic tank pumped and fixed the drainage lines this weekend.
My question is this: I don't want it to happen again, and if it does, I don't want overflow to go anywhere near the remodeled side of the basement. The other half is the garage. My idea is to put in a slop sink, a good 5-6' away from the dividing wall between the garage/finished basement. That will be a "sacrificial" drain of sorts, the first place a backup will show, semi-safely away from the remodeling work. The problem I see is the height of the main septic line and the washing machine drain. The drain of the sink would need to be higher the height of the main septic line, but lower than the washer drain, correct?
I'm linking to a picture of the plumbing there (with the backside section of a wall torn out to check for water damage). The washer drain is on the far right, the pinkish light is coming from the other side of the wall and is the inlet of the drain.
One idea floating in my head is to raise the height of the washing machine drain and run the sink plumbing off that lowest line coming out of the main septic line.
To visualise my plan:
Is this a good idea? Will it work? Any better ideas? I really just want to protect my hard work on the other side of the wall.