This seems obvious, but I have learned to never assume things.

I am having problems with drainage backup to my Septic tank. The toilet will flush once, then the second time it backs up and some water will backup into the tub. The tub also backs up after showering for 2-3 minutes. It will backup right away if you shower after flushing the toilet.

I uncovered the tank and opened the LINE IN inspection port. I had my wife flush the toilet and watched the INTAKE Pipe going into the Septic tank. There was a slow drip when I first opened the port and it really didn't speed up when she flushed the toilet. I then had her run the Kitchen sink which hasn't shown any backup issues. The slow drip never sped up with that running either.

Shouldn't I see water gushing out when the toilet is flushed and the sink is ran?

This lead me to believe there is a blocking issue somewhere after all the drains converge into a junction or possibly at that junction itself.

Is this an accurate evaluation?

Thanks...

Shouldn't I see water gushing out when the toilet is flushed and the sink is ran?
This lead me to believe there is a blocking issue somewhere after all the drains converge into a junction or possibly at that junction itself.


Yes,you should see a spurt of water entering the septic tank a minute or so after you flush a toilet. Since the manifold (junction box) is located at the outlet of the tank and your prblem's between te house and the tank, you DID open up the house cleanout to determine the problem's outside the house and not inside didn't you? this leads me to believe you have a partial blockage that's blocking a full flow but allowing some discharge to trickle through. Snake out the sewer line to the tank after you determine exactly where the clog is, sewer line or house system. Good luck, Tom