First a little setup. This is for a septic system installation and deals only with the sewer line between the house and septic tank. Code and good construction calls for a sewer cleanout within a few feet of the foundation, where the pipe exits the house, so you can snake the line between the house and tank. Further, there is a call for a cleanout every (fill in the blank, 50/100') along the sewer line to insure that the snake will be able to reach the full length between point A and B.
There is also a requirement that says: "A cleanout is required ahead of the septic tank anytime a bend of 45 degrees or more is used."
However, the requirement does not specify if the additional cleanout goes upstream (between the house cleanout and bend) or downstream (between the bend and septic tank) of the bend.
It stands to reason that the intention of the cleanout is to clean out a plugged line. It also stands to reason (to me at least) that from the cleanout at the structure you can access the upstream side of a bend to push a plug through and beyond the bend, and installing another cleanout close to the bend would be redundant. And that by not having a cleanout downstream of the bend access to the line between the bend and the septic tank would be hindered in the case of a plug at the incoming baffle of the septic tank.
I can't find any code language that specifies which side of the bend to install on.
I reason that it should be downstream of the bend.
What say you all?

iamgrowler

The clean-out goes before the change in direction.

akfiretuck

Thanks for the reply.
First, what is your source for reference?
Second, does this mean that you advocate two cleanouts upstream of the bend and, by default, none downstream? Or are you suggesting the requirement should probably read 'add two cleanouts, one upstream and another downstream?'
Last, knowing the answer, according to some source is one thing but understanding why the redundancy without the downstream access is confusing to me. Why is it this way?