I have some obstacles that limit the amount of initial drop (plumbing in a concrete slab) allowed in the bathroom group and wondered if it is OK to discharge a water closet directly into a sanitary tee (inlet of the tee pointing upwards)? Can the closet flange be shortened (sawed off) to further gain vertical space? Does the plumbing have to be below the slab or can it be 'in' the slab? What are the limitations? Can a basin discharge vertically into the top of the 4" drain pipe or does it have to enter at an angle?
Thank you.

I have some obstacles that limit the amount of initial drop (plumbing in a concrete slab) allowed in the bathroom group and wondered if it is OK to discharge a water closet directly into a sanitary tee (inlet of the tee pointing upwards)? Can the closet flange be shortened (sawed off) to further gain vertical space? Does the plumbing have to be below the slab or can it be 'in' the slab? What are the limitations? Can a basin discharge vertically into the top of the 4" drain pipe or does it have to enter at an angle?
Thank you.
Hi Camel,
It is OK to discharge a water closet directly into a sanitary tee (inlet of the tee pointing upwards)?
Yes.
Can the closet flange be shortened (sawed off) to further gain vertical space?
Since the closet flange already sets on the floor it makes no sense to shorten it. Did you mean something else?
Does the plumbing have to be below the slab or can it be 'in' the slab?
Our codes specify that the drainage shall be in trenches under the poured slab. However check with your building department to see.
Can a basin discharge vertically into the top of the 4" drain pipe or does it have to enter at an angle?
I don't understand the question. Are you asking if a wash basin without a trap may be discharged into a existing floor drain? And please explain, "does it have to enter at an angle?"
Regards, Tom

Hi Camel,
it is OK to discharge a water closet directly into a sanitary tee (inlet of the tee pointing upwards)?
Yes.
Can the closet flange be shortened (sawed off) to further gain vertical space?
Since the closet flange already sets on the floor it makes no sense to shorten it. Did you mean something else?
Does the plumbing have to be below the slab or can it be 'in' the slab?
Our codes specify that the drainage shall be in trenches under the poured slab. However check with your building department to see.
Can a basin discharge vertically into the top of the 4" drain pipe or does it have to enter at an angle?
I don't understand the question. Are you asking if a wash basin without a trap may be discharged into a existing floor drain? And please explain, "does it have to enter at an angle?"
Regards, Tom
Bad wording of the question... basin is the last unit before exiting the building and am guessing after the P-trap the discharge line will go back a foot or so, drop down and pick up a 1 1/2" sanitary tee sized to fit into the 4" main drain pipe that is coming from the water closet after first originating at the shower.

Bad wording of the question...basin is the last unit before exiting the building and am guessing after the P-trap the discharge line will go back a foot or so, drop down and pick up a 1 1/2" sanitary tee sized to fit into the 4" main drain pipe that is coming from the water closet after first originating at the shower.

Hi Camel,
"Im guessing after the P-trap the discharge line will go back a foot or so, drop down and pick up a 1 1/2" sanitary tee sized to fit into the 4" main drain pipe that is coming from the water closet after first originating at the shower"

Let me explain the way it should go. After the 2" "P" trap the discharge line will go into the wall and a 2" sanitary tee. The upper part of the tee will go (1)to a roof vent or (2) a AAV,(Air Admittance Valve). The bottom of the tee will drain directly into a 4 X 2" combo or a sanitary tee.
Is the shower unvented also? Regards, Tom

Hi Camel,
"Im guessing after the P-trap the discharge line will go back a foot or so, drop down and pick up a 1 1/2" sanitary tee sized to fit into the 4" main drain pipe that is coming from the water closet after first originating at the shower"

Let me explain the way it should go. After the 2" "P" trap the discharge line will go into the wall and a 2" sanitary tee. The upper part of the tee will go (1)to a roof vent or (2) a AAV,(Air Admittance Valve). The bottom of the tee will drain directly into a 4 X 2" combo or a sanitary tee.
Is the shower unvented also? regards, Tom
Yes, the shower is presently unvented.

Yes, the shower is presently unvented.
If you vent the lavatory and the shower connects to the lavatory drain then the shower is wet vented. Regards, Tom