Over the past two months or so we have had a problem with the wash machine's water coming back up the stand pipe when the machine drains. This happens after one load.

We had the septic pumped (it needed it, but that's another post), and the guy, while he was pumping the system had me fill the washer and put it into spin to get the water to drain out fast. He never saw the water come into the tank. When I flushed the toilets, he saw that.

Well, I thought that I might just put a garden hose-minus the metal end-into the stand pipe, perhaps there is a who-knows-what-there. Anyway, after putting about 15ft. Into the pipe, I ran out of hose. I still have the problem.

BTW, the wash machine is in the basement a few feet from where the septic tank is. How long can the stand pipe be before it connect to the main inlet pipe?

Thanks in advance!

the guy, while he was pumping the system had me fill the washer and put it into spin to get the water to drain out fast. He never saw the water come into the tank.
No wonder! On septic systems both the kitchen sink and the washer are on a separate drain line that goes into a grease trap (see image) before it goes into the septic tank to be processed, You have a clog in the line leading to the grease trap, %The grease trap is there to intercept the grease from the kitchen and the lint from the washer before it gets out in the drainfield and clogs it up. If you don't know you have a grease trap it probably should be serviced. The solution would be to snake the washer line and open up the grease trap. Good luck, Tom

Thanks Tom!