Hello,

I am remodeling my kitchen and moving the kitchen sink to a wall. The wall has the soil stack coming down from the upstairs toilet. Is it OK to tap into the soil stack for the kitchen drain? The old sink location was in a "bar" between the living room and kitchen. The drain goes into the floor. Since my new floor will be stained concreate anyway, can I convert that old sink drain pipe to a floor drain?

Very best regards,
Bill
Dallas, TX

I am remodeling my kitchen and moving the kitchen sink to a wall. The wall has the soil stack coming down from the upstairs toilet. Is it OK to tap into the soil stack for the kitchen drain? No! You would be discharging a major fixture past a unvented minor one and that's a no-n0.
You may connect to the stack only if you run a separate vent. Another option would be to install a AAV,(Air Admittance Vent) (see image) And since you ask,
can I convert that old sink drain pipe to a floor drain just study the image I've put up. Good luck, Tom