Please comment on my plumbing system design....

Would appreciate any comments on my proposed plumbing system before I start cutting and joining...

Thanks in advance for any and all advice...

Chris

system

It is too small to make out much detail, but the three things that come to mind immediately are;
1. You cannot have the backward connection where it turns to the septic tank.
2. The end cleanout also appears to be backwards.
3. You cannot, or at least should not, run the vent through the side wall.

Thank you very much for your comments- I really appreciate it...

Could you explain what you mean by a "backwards connection"? Do you mean having two drain flows coming at each other and meeting together where the line exits to the septic tank?

Similarly, does the "end clean out" refer to the one at the end of run above?

The home is a timber frame structure with blocking between the exposed rafter tails. I thought it would be ok to run a vent through this blocking between the rafter tails outside....Would it be better to use an AAV in this case than to run the vent outside under the eave between the rafters?

Thanks again for your comments....

Chris

system

Could you explain what you mean by a "backwards connection"? Do you mean having two drain flows coming at each other and meeting together where the line exits to the septic tank?

Similarly, does the "end clean out" refer to the one at the end of run above?

Yes to both of the above. If you use an AAV, it does not have to be extended to a point outside the building. If you do use a AAV, however, since it appears that the drain portion will be connected at the lowest point in the sewer system, if the line to the septic tank floods, for any reason not just because of a stoppage, that sink will not drain even though everything else might operate normally.

Thank you for clarifying. I have figured out a way to route a vent from that last sink to a tie in with the toilet vent which runs up to the main stack up on the second floor.

It would be ok wouldn't it, to run that last drain line as drawn towards the oncoming line but have it drop in from the top where they meet?

Thanks again,

Chris

drain

I am not sure what you mean, but there are many ways that right hand drain could be connected maintaining proper flow direction.

Could you post a larger version?

new schematic (bigger with a few changes)

Thanks again for all comments...