How close to surface of slab can drain pipe be run?

[derekmw]

Location: California

I'm very new to plumbing and trying to add the drain pipes needed for a new bathroom I am adding. This bathroom is adjacent to our existing kitchen. I plan to run the bathroom pipe over to this kitchen perpendicular to it, and tie into and replace the existing 2" from that point to the main with 3".

The point where I will tie into is 6" under the slab at the top of the drain pipe. the furthest point in the bathroom from kitchen is my shower drain at 19 ft away. So based on that, the pipe at this shower will need to be 4 3/4" higher, correct? if so, that means that it will only be 1 1/4" below the slab. Is this allowed by code? Do I just wrap this section that will be in the concrete with foam? I have a feeling you cannot do this but wanted to get some advice.

I have some room at the kitchen where I will tie into, where I can lower it another 1" and still maintain the grade needed from that point to the main. But even if I did that, it will only be 2 1/4" deep at this new shower drain, which will still be partially in the concrete slab.

Any advice would be greatly appreciated!

 

[John Gayewski]

There is no minimum depth. Your concrete will suffer greatly from having a pipe in it. Be prepared for a crack or make a new plan.

 

[Sponsor]

 

[derekmw]

Thank you for the reply.

Since this is the shower, the pipe will make a long 90 in that red square outline and then a p-trap to the left of that. Also of course the flooring of the shower will be quite a bit higher. The wall of the shower is along that long run where the pipe gets closer to the surface (3ft long wall). The rest of the flooring in this area is going to be tile.

Is there any issues with having cracks in the concrete right there other than appearance? If so, I don't mind, but I don't want to keep it this way if it will cause issues down the line.