Connecting cellar drain to septic line

[James23912]

Hi I am needing to connect my horizontal 3” line in the cellar to the 4” line going thru the foundation to the septic tank. The 3” stops about 30” from the wall and the exit hole is about 40” lower than the 3”, I Have laid out a diagonal line already , going at an angle, but want to ask if that is the best way as opposed to extending the 3” straight and then dropping down directly vertical using an 90 or sweep , thanks

 

[LLigetfa]

Is this new construction or a reno? Does the 4 inch line have a clean-out? If not, I would place a Y with clean-out on the end of the 4 inch and feed the 3 inch into the Y rolling them if need be. I would not use a 90 but rather an angle that will match the Y.

 

[Sponsor]

 

[Tuttles Revenge]

Plumbing fittings that connect a vertical drain to a horizontal drain need to come together in a 45 as LLigetfa mentioned. Transitioning from vertical to horizontal requires long sweep fittings so that the change of direction of the waste is more gradual. A long sweep 90 or 2 - 45's creates this transition.