I want to relocate the main bath toilet in my small bathroom. This will place it several feet from the main stack which is now adjacent to the toilet. There is a main stack cleanout in the basement. I need to have my new toilet wasteline go about 5' horizontal (with proper pitch) and then drop 7' at about a 45% angle tying it into the current cleanout. I will add a new cleanout towards the bottom of this run. Two questions:

1) Will proper venting be a problem? I could vent the new line into the now disabled Y that served the old toilet as it begins its drop downward.

2) Is the 7' drop at 45% improper for toilet waste? I think I've heard that the water not move the solid waste along properly if the angle is too sharp?

Can you just extend the existing toilet waste line to the new location ? Meaning: remove the closet ring, 90 bend, attach new pipe and run it to the new location in the floor / ceiling...

Do you have framed floor / ceiling ? What is size of your joists ?

No, I can't use the existing waste line because there is not enough room to allow for the necessary drop (1/4" per foot) in the distance I need to travel. It was basically a tee from the stack plus 12" and tucked up between two 2x8 floor joists and located tight up against the flooring.

Yes, I have a framed floor/ceiling. The joists are 2X8.

there is not enough room to allow for the necessary drop (1/4" per foot) in the distance I need to travel. And what would that distance be? 1/8 th. Drop to the foot would cut the drop in half. Would that work for you? Back to you, Tom

I need to have my new toilet wasteline go about 5' horizontal (with proper pitch) I can't use the existing waste line because there is not enough room to allow for the necessary drop (1/4" per foot) in the distance I need to travel
Then reduce the pitch to 1/8th. Per foot and cut the slope in half.

1) Will proper venting be a problem? I could vent the new line into the now disabled Y that served the old toilet as it begins its drop downward.
Would you still need to vent if you used the old drain line?

2) Is the 7' drop at 45% improper for toilet waste? I think I've heard that the water not move the solid waste along properly if the angle is too sharp?
No, we 45% down all the time when we connect the house sewer to the street raiser.
Let me know if reducing the pitch helps. Good luck, Tom